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1. Which feature is considered a defining property that is present in all living organisms?
ⓐ. Reproduction
ⓑ. Metabolism
ⓒ. Locomotion
ⓓ. Photosynthesis
Correct Answer: Metabolism
Explanation: Metabolism refers to the sum total of all chemical reactions occurring inside a living body. These reactions include both building-up processes (anabolism) and breaking-down processes (catabolism). It highlights metabolism as a universal property because every living cell performs chemical reactions to maintain life. Even organisms that do not reproduce (like mules) still carry out metabolic reactions. Without metabolism, energy transfer and maintenance of cellular functions cannot happen. Therefore, metabolism is treated as a key defining feature of living organisms.
2. In , which characteristic is described as the “most obvious” feature of living organisms?
ⓐ. Growth
ⓑ. Consciousness
ⓒ. Metabolism
ⓓ. Cellular organisation
Correct Answer: Growth
Explanation: Growth is described as the most obvious feature because it can be easily observed externally in living organisms over time. Living organisms increase in mass and number of cells through internal processes like cell division. It also clarifies that growth alone cannot be the only defining property, because some non-living things (like crystals) can also grow by external accumulation. However, living growth is internal and controlled by cellular activity. This makes growth a prominent and visible sign of life.
3. What does state as the unique feature that makes living beings able to respond to their surroundings?
ⓐ. Reproduction
ⓑ. Nutrition
ⓒ. Consciousness
ⓓ. Movement
Correct Answer: Consciousness
Explanation: Consciousness is the ability of an organism to sense and respond to environmental stimuli such as light, temperature, touch, chemicals, or sound. It treats this as a uniquely defining property of living organisms because it reflects awareness and response capability. Even plants show responses, such as bending toward light, which indicates sensitivity to stimuli. This property includes perception and reaction mechanisms controlled by internal systems. Because of this, consciousness is considered a very important characteristic of life.
4. Which statement best represents conclusion about reproduction as a defining property of life?
ⓐ. Reproduction is absent in all plants.
ⓑ. Reproduction is the only universal feature of life.
ⓒ. Reproduction cannot be a defining property because it does not occur in all living organisms.
ⓓ. Reproduction is present only in animals.
Correct Answer: Reproduction cannot be a defining property because it does not occur in all living organisms.
Explanation: It explains that reproduction is an important biological process for continuity of a species, but it is not universal across all living individuals. For example, sterile worker bees, infertile couples, and mules do not reproduce, yet they are undoubtedly living. A defining property must be present in all living organisms without exception. Since reproduction can be absent in some living organisms due to biological or functional reasons, it cannot be considered the sole defining feature of life.
5. In the taxonomic hierarchy, which category comes immediately above “species”?
ⓐ. Family
ⓑ. Class
ⓒ. Order
ⓓ. Genus
Correct Answer: Genus
Explanation: In biological classification, species is the basic unit and groups together organisms that can interbreed and produce fertile offspring. The next higher category is genus, which includes one or more closely related species. For example, Panthera includes Panthera leo (lion) and Panthera tigris (tiger), showing species grouped under one genus. This grouping is based on shared structural and evolutionary similarities. Therefore, genus is placed immediately above species in the hierarchy.
6. In binomial nomenclature, which part of the scientific name is written first?
ⓐ. Generic name (Genus)
ⓑ. Specific epithet (Species)
ⓒ. Family name
ⓓ. Order name
Correct Answer: Generic name (Genus)
Explanation: Binomial nomenclature assigns a two-word scientific name to every organism to ensure universal and standardized identification. The first word is the generic name, indicating the genus to which the organism belongs. This genus name starts with a capital letter and is followed by the specific epithet written in lowercase. Together, they uniquely identify a species and show its close relationship with other species in the same genus. This internationally accepted method avoids confusion caused by local or common names.
7. Which taxonomical aid is specifically designed as a “storehouse” of collected plant specimens that are preserved for study?
ⓐ. Zoological park
ⓑ. Herbarium
ⓒ. Museum
ⓓ. Botanical garden
Correct Answer: Herbarium
Explanation: A herbarium is a systematically arranged collection of plant specimens that are dried, pressed, and mounted on sheets for permanent record. Each specimen sheet typically contains detailed information like the scientific name, family, place of collection, date, and collector’s name. Herbariums serve as reference materials for identification, classification, and research in taxonomy. They help compare unknown plants with preserved samples and support scientific studies over long periods. Because of their organized and permanent nature, they are considered essential taxonomical aids.
8. Which of the following resources is most directly used for identifying organisms using paired contrasting statements?
ⓐ. Museum
ⓑ. Botanical garden
ⓒ. Zoological park
ⓓ. Key
Correct Answer: Key
Explanation: A key is a taxonomical tool used for identification of plants and animals through a series of paired, contrasting statements. These paired statements are called couplets, and each choice leads the learner to the next relevant step until the organism is identified. Keys are widely used in taxonomy because they provide a logical pathway to reach the correct name using observable characters. They are especially helpful when dealing with many similar species. Thus, keys are one of the most practical tools for identification.
9. defines “taxonomy” primarily as the study of which set of activities?
ⓐ. Naming, describing, and classifying organisms
ⓑ. Measuring body organs and tissues
ⓒ. Studying only animal behavior in nature
ⓓ. Studying chemical reactions in cells
Correct Answer: Naming, describing, and classifying organisms
Explanation: Taxonomy is the branch of biology that deals with identification, nomenclature (naming), and classification of organisms. It emphasizes taxonomy as the foundational discipline that helps organize the vast diversity of living forms into systematic categories. It provides a structured way to study organisms based on similarities, differences, and relationships. By assigning universal scientific names and placing organisms into ranks, taxonomy prevents confusion created by regional names. This makes taxonomy essential for clear biological communication worldwide.
10. Which one of the following best describes “systematics” as per in relation to taxonomy?
ⓐ. Study of only naming organisms without classification
ⓑ. Study of only fossil organisms
ⓒ. Study of diversity and evolutionary relationships among organisms
ⓓ. Study of chemical composition of tissues
Correct Answer: Study of diversity and evolutionary relationships among organisms
Explanation: Systematics is a broader field that includes taxonomy but also focuses on evolutionary relationships among organisms. It explains that systematics deals with the identification, naming, and classification of organisms along with understanding their evolutionary history and relatedness. It attempts to explain why organisms share similarities by linking them through ancestry. This approach helps build phylogenetic relationships and gives a deeper understanding of biodiversity. Therefore, systematics is considered taxonomy plus evolutionary interpretation.
11. Which statement best supports metabolism as a defining feature of living organisms?
ⓐ. All living organisms have a rigid cell wall.
ⓑ. All living organisms carry out chemical reactions continuously inside their cells.
ⓒ. All living organisms show fast movement from place to place.
ⓓ. All living organisms reproduce at least once in their lifetime.
Correct Answer: All living organisms carry out chemical reactions continuously inside their cells.
Explanation: Metabolism means the total of all chemical reactions occurring inside a living organism. These reactions run continuously to maintain essential life processes like energy production, repair, and synthesis of biomolecules. Even when an organism is resting, its cells keep performing biochemical reactions. This constant internal chemical activity is necessary for survival and maintenance of life. Because every living organism shows metabolic activity, it is treated as a universal feature. Hence, metabolism strongly supports the living state.
12. Metabolism is described as the sum total of which processes occurring in an organism?
ⓐ. Digestion and excretion only
ⓑ. Reproduction and growth
ⓒ. Anabolism and catabolism
ⓓ. Photosynthesis and locomotion
Correct Answer: Anabolism and catabolism
Explanation: Metabolism includes two broad categories of reactions: anabolism and catabolism. Anabolism involves building complex molecules from simpler ones, supporting growth and repair. Catabolism involves breaking complex molecules into simpler ones, releasing energy needed for cellular activities. Both sets of reactions operate together to keep the organism functioning. This combined chemical activity represents the complete metabolic state of a living body. Therefore, metabolism is correctly described as anabolism plus catabolism.
13. Which idea correctly explains why metabolism is a more reliable defining property than growth?
ⓐ. Growth never happens in living organisms, but metabolism does.
ⓑ. Growth is always faster than metabolism, so metabolism is not useful.
ⓒ. Metabolism occurs only in plants, but growth occurs in all organisms.
ⓓ. Metabolism is performed by all living organisms at all times, whereas growth can also occur in non-living objects.
Correct Answer: Metabolism is performed by all living organisms at all times, whereas growth can also occur in non-living objects.
Explanation: Metabolism refers to internally controlled biochemical reactions that occur only in living cells. It is present continuously in all living organisms, regardless of their size or complexity. Growth, however, is not always a reliable marker because non-living objects can also increase in size by external deposition. Metabolic reactions reflect active, regulated functioning within the body. This makes metabolism a stronger and more universal indicator of life. Therefore, metabolism is more reliable than growth as a defining property.
14. Which of the following is true about metabolism in living organisms?
ⓐ. Metabolism happens only in the presence of sunlight.
ⓑ. Metabolism occurs only during active movement.
ⓒ. Metabolism occurs in all living cells regardless of body size.
ⓓ. Metabolism is absent in microorganisms.
Correct Answer: Metabolism occurs in all living cells regardless of body size.
Explanation: Metabolism is a cellular property, meaning it operates wherever living cells exist. Whether an organism is unicellular like bacteria or multicellular like humans, each living cell performs biochemical reactions. These reactions maintain cell structure, produce energy, and regulate internal balance. Body size does not determine the presence of metabolism; living cellular activity does. Even the smallest living organisms carry out metabolism to survive. Hence, metabolism occurs in all living cells irrespective of body size.
15. Which statement correctly connects metabolism with “living state”?
ⓐ. Metabolism proves an organism is living because it shows active internal chemical functioning.
ⓑ. Metabolism proves an organism is living only if it has a brain.
ⓒ. Metabolism proves an organism is living only if it reproduces.
ⓓ. Metabolism proves an organism is living only if it grows externally.
Correct Answer: Metabolism proves an organism is living because it shows active internal chemical functioning.
Explanation: Metabolism represents the continuous internal biochemical functioning of living cells. Through metabolic reactions, organisms generate energy, build and repair tissues, and maintain internal stability. This internal activity is essential for life and continues even when no visible growth or reproduction is occurring. The living state depends on regulated chemical processes happening within the body. Because metabolism reflects this active internal functioning, it directly supports whether an organism is alive. Thus, metabolism is strongly linked to the living state.
16. Which of the following best describes why non-living objects do not show metabolism?
ⓐ. Non-living objects cannot be seen with a microscope.
ⓑ. Non-living objects always contain DNA and RNA.
ⓒ. Non-living objects only exist in water.
ⓓ. Non-living objects lack cellular organization required for controlled chemical reactions.
Correct Answer: Non-living objects lack cellular organization required for controlled chemical reactions.
Explanation: Metabolism requires a living cellular framework where biochemical reactions are coordinated and regulated. Cells provide enzymes, membranes, and organized pathways that control how reactions occur. Non-living objects do not possess cells, enzymes, or internal regulation systems. Any chemical change in non-living matter is not part of a coordinated life-sustaining network. Since cellular organization is essential for controlled biochemical pathways, metabolism cannot occur without it. Therefore, non-living objects do not show metabolism due to lack of cellular organization.
17. Metabolism is treated as a defining feature because it occurs even in organisms that do not reproduce. Which example best supports this idea?
ⓐ. Fire shows metabolism because it uses oxygen.
ⓑ. Mule is living and shows metabolism despite being sterile.
ⓒ. Crystal is living and shows metabolism during growth.
ⓓ. Stone reproduces and shows metabolism.
Correct Answer: Mule is living and shows metabolism despite being sterile.
Explanation: A mule is a sterile organism and cannot reproduce, yet it performs all essential life processes. Its cells carry out respiration, digestion, circulation, and energy production continuously. These are metabolic activities that maintain the organism’s survival and functioning. This shows that metabolism is present regardless of reproductive ability. Since a defining property must exist even when reproduction is absent, metabolism becomes a stronger universal marker of life. Hence, the sterile mule example supports metabolism as a defining feature.
18. Which statement best distinguishes metabolic reactions from ordinary chemical reactions?
ⓐ. Metabolic reactions always release light energy.
ⓑ. Metabolic reactions happen only outside the body.
ⓒ. Metabolic reactions are enzyme-controlled and occur within living cells.
ⓓ. Metabolic reactions are never related to energy.
Correct Answer: Metabolic reactions are enzyme-controlled and occur within living cells.
Explanation: Metabolic reactions take place within living cells under strict regulation and coordination. They are controlled by enzymes, which ensure reactions happen at appropriate rates and in specific sequences. Cells organize these reactions into pathways that support survival, growth, and maintenance. This regulation and organization are essential characteristics of metabolism. The presence of enzyme-controlled pathways reflects living cellular activity. Therefore, enzyme control within living cells is the key distinguishing feature of metabolic reactions.
19. Metabolism includes the chemical reactions related to which essential life requirement?
ⓐ. Maintenance and survival of the organism through energy and material transformation
ⓑ. Only external body movement
ⓒ. Only communication by sound
ⓓ. Only the formation of gametes
Correct Answer: Maintenance and survival of the organism through energy and material transformation
Explanation: Metabolism includes reactions that convert nutrients into energy and useful cellular materials. These transformations support repair, growth, regulation, and removal of wastes, all of which are required for survival. The body depends on metabolic reactions to maintain internal balance and continuous functioning. Without energy conversion and material synthesis, cells cannot perform their roles. Thus, metabolism is directly tied to maintenance and survival needs. Therefore, metabolism includes reactions for energy and material transformation essential for life.
20. Which conclusion is correct regarding metabolism as a “living definition marker”?
ⓐ. Metabolism occurs only after reproduction starts.
ⓑ. Metabolism occurs only in animals, so it cannot define all life.
ⓒ. Metabolism is optional and may be absent in some living cells.
ⓓ. Metabolism is present in all living organisms and is therefore a universal defining property.
Correct Answer: Metabolism is present in all living organisms and is therefore a universal defining property.
Explanation: Metabolism occurs in every living organism because it is required to sustain cellular functions. From unicellular organisms to complex multicellular organisms, biochemical reactions operate continuously within cells. These reactions enable energy production, synthesis of biomolecules, and regulation of internal conditions. Since a defining property must be universal and present without exception, metabolism fits this criterion strongly. It remains present even when other features like reproduction may be absent. Hence, metabolism is a universal defining property of life.
21. Which characteristic refers to the ability of an organism to sense its surroundings and respond to stimuli?
ⓐ. Growth
ⓑ. Consciousness
ⓒ. Reproduction
ⓓ. Classification
Correct Answer: Consciousness
Explanation: Consciousness is the ability of living organisms to detect changes in their environment and respond appropriately. Stimuli may include light, temperature, sound, touch, chemicals, or pressure. This response is possible due to coordinated internal systems that receive signals and generate reactions. Even simple organisms show basic responses, proving it is a fundamental life property. This feature reflects awareness and sensitivity, which are hallmarks of living systems. Hence, consciousness is directly linked to stimulus-response behavior.
22. Which statement best explains why consciousness is considered a unique defining property of living organisms?
ⓐ. Only living organisms have a fixed crystalline structure.
ⓑ. Only living organisms exist without cellular organization.
ⓒ. Only living organisms can respond to environmental changes in a controlled manner.
ⓓ. Only living organisms can increase in size by external accumulation.
Correct Answer: Only living organisms can respond to environmental changes in a controlled manner.
Explanation: Consciousness involves detecting stimuli and producing a meaningful response through internal coordination. This response is regulated and purposeful, not random. Living systems can sense changes and adjust behavior or physiology to maintain survival. Such controlled response shows active internal regulation. This makes consciousness a strong defining property of life. Therefore, controlled stimulus-response is a unique feature of living organisms.
23. Which of the following is the best example of consciousness in plants?
ⓐ. Rusting of iron in air
ⓑ. Growth of a crystal in a saturated solution
ⓒ. Melting of wax on heating
ⓓ. Bending of shoots towards light
Correct Answer: Bending of shoots towards light
Explanation: Plants show consciousness through their ability to sense and respond to environmental stimuli. When a plant shoot bends toward light, it is responding to the direction of light through internal growth regulation. This response helps the plant maximize photosynthesis and survival. The action is coordinated and not a simple physical change. Such stimulus-response behavior indicates sensitivity. Hence, bending toward light is a clear example of consciousness in plants.
24. Which term best describes an organism’s response to a stimulus as an immediate indicator of being alive?
ⓐ. Mineralization
ⓑ. Consciousness
ⓒ. Crystallization
ⓓ. Evaporation
Correct Answer: Consciousness
Explanation: Consciousness includes the capacity to sense and react to external changes such as touch, light, heat, or chemicals. This property indicates that the organism has functioning internal mechanisms that can perceive a stimulus and produce a response. Responses may be quick or slow, but they are regulated and purposeful. This ability is a direct sign of living activity. It reflects the organism’s active connection with its environment. Therefore, stimulus-response behavior is best described as consciousness.
25. Which feature links consciousness with survival advantage in living organisms?
ⓐ. Ability to remain unchanged in all environments ensures survival.
ⓑ. Ability to grow only by external accumulation improves fitness.
ⓒ. Ability to respond to stimuli helps organisms avoid harm and obtain resources.
ⓓ. Ability to exist without metabolism ensures continuity.
Correct Answer: Ability to respond to stimuli helps organisms avoid harm and obtain resources.
Explanation: Consciousness enables organisms to detect threats and opportunities in their environment. By responding to stimuli, organisms can escape harmful conditions and move toward favorable resources like food, water, or light. Such adaptive responses increase chances of survival and success. Responses may involve behavior, physiology, or growth changes depending on the organism. This regulated reaction demonstrates active life processes. Hence, stimulus response directly supports survival advantage.
26. Which of the following best represents consciousness in microorganisms?
ⓐ. Expanding volume due to heating
ⓑ. Increasing size by deposition of minerals
ⓒ. Breaking into pieces due to pressure
ⓓ. Movement away from harmful chemicals
Correct Answer: Movement away from harmful chemicals
Explanation: Many microorganisms show stimulus-response behavior called taxis, where they move toward beneficial substances or away from harmful ones. This reflects consciousness because the organism senses a chemical stimulus and responds by changing its movement. The response is coordinated through cellular mechanisms even without a nervous system. Such behavior improves survival by avoiding toxic conditions. This indicates the organism is actively interacting with its surroundings. Therefore, moving away from harmful chemicals is a valid example of consciousness.
27. Which process is most directly associated with consciousness rather than simple physical change?
ⓐ. Expansion of metal on heating
ⓑ. Reflex response to heat
ⓒ. Boiling of water
ⓓ. Sublimation of camphor
Correct Answer: Reflex response to heat
Explanation: A reflex response to heat involves sensing a stimulus and producing a rapid, coordinated reaction to protect the body. This shows stimulus detection and purposeful response, which are key parts of consciousness. The response requires internal control systems to receive and act on the signal. Physical changes like expansion, boiling, or sublimation occur without sensing or regulation. Conscious responses are adaptive and protective. Hence, reflex response to heat is directly linked to consciousness.
28. Which of the following best describes consciousness as a life property?
ⓐ. It is the ability to remain completely inactive.
ⓑ. It is the ability to show only visible growth.
ⓒ. It is the ability to form crystals under suitable conditions.
ⓓ. It is the ability to sense and respond to stimuli, present across living organisms.
Correct Answer: It is the ability to sense and respond to stimuli, present across living organisms.
Explanation: Consciousness is defined by the ability to detect environmental changes and respond accordingly. This includes response to light, temperature, chemicals, touch, and other stimuli. The property is seen widely across living organisms, including plants, animals, and microorganisms. Responses can be behavioral or growth-based, but they are regulated. This indicates internal coordination and sensitivity. Therefore, sensing and responding to stimuli best defines consciousness.
29. Which statement correctly connects consciousness with internal coordination?
ⓐ. Consciousness exists only in non-living matter due to chemical changes.
ⓑ. Consciousness depends only on external pressure without any internal control.
ⓒ. Conscious responses require organized internal mechanisms to detect and act on stimuli.
ⓓ. Conscious responses happen only when an organism is sleeping.
Correct Answer: Conscious responses require organized internal mechanisms to detect and act on stimuli.
Explanation: Consciousness involves more than a change; it requires a system that can sense a stimulus and produce a controlled response. This needs internal organization such as receptors, signaling pathways, and effectors. The organism must first detect the stimulus and then generate an appropriate action. Such coordination shows integrated functioning of living systems. Even unicellular organisms use cellular signaling for responses. Hence, organized internal mechanisms are essential for conscious responses.
30. Which of the following is the most accurate statement about consciousness in living beings?
ⓐ. It is shown by both plants and animals through stimulus-response behavior.
ⓑ. It is limited only to animals with a nervous system.
ⓒ. It occurs only during reproduction.
ⓓ. It is absent in unicellular organisms.
Correct Answer: It is shown by both plants and animals through stimulus-response behavior.
Explanation: Consciousness is expressed as the ability to sense stimuli and respond, and it is not restricted only to animals. Plants show responses like bending toward light and closing leaves on touch, indicating sensitivity. Animals show faster and more complex responses, but the basic property is the same. Even simpler organisms can respond to chemicals and environmental changes. The key idea is stimulus-response, not the presence of a nervous system. Therefore, consciousness is shown across living organisms, including plants and animals.
31. What does “cellular organisation” primarily mean in living organisms?
ⓐ. Living bodies are made only of minerals arranged in layers.
ⓑ. Living bodies are formed by random mixing of chemicals without structure.
ⓒ. Living bodies exist only as crystals in solution.
ⓓ. Living bodies are made up of one or more cells that act as structural and functional units.
Correct Answer: Living bodies are made up of one or more cells that act as structural and functional units.
Explanation: Cellular organisation means that every living organism is built from cells. The cell is the smallest unit capable of performing life functions such as metabolism, growth, repair, and response. In unicellular organisms, one cell performs all life processes, while in multicellular organisms, many cells cooperate. This organized arrangement allows formation of tissues, organs, and systems for efficient functioning. Life activities depend on coordinated cellular work rather than random chemical mixing. Hence, cellular organisation is a key feature of living beings.
32. Which statement best explains why cellular organisation supports life functions?
ⓐ. Cells prevent all chemical reactions inside the body.
ⓑ. Cells provide a controlled environment where life processes occur in an organized manner.
ⓒ. Cells exist only in non-living objects.
ⓓ. Cells ensure an organism remains completely unchanged over time.
Correct Answer: Cells provide a controlled environment where life processes occur in an organized manner.
Explanation: Cells create a regulated internal environment where biochemical reactions can occur efficiently. Membranes control the entry and exit of substances, helping maintain balance. Enzymes and cellular structures ensure reactions happen in proper sequences and at suitable rates. This organized framework allows respiration, synthesis, transport, and regulation to occur smoothly. Without cellular organisation, reactions would be uncoordinated and unable to sustain life. Therefore, cells support life by providing controlled, organized functioning.
33. In the context of cellular organisation, what distinguishes unicellular organisms from multicellular organisms?
ⓐ. Unicellular organisms have no metabolism, while multicellular organisms do.
ⓑ. Multicellular organisms have no cellular organisation.
ⓒ. Unicellular organisms perform all life processes within one cell, while multicellular organisms show division of labour among many cells.
ⓓ. Unicellular organisms are always larger than multicellular organisms.
Correct Answer: Unicellular organisms perform all life processes within one cell, while multicellular organisms show division of labour among many cells.
Explanation: Unicellular organisms consist of a single cell, and that one cell performs all vital functions. Multicellular organisms contain many cells that become specialized for different tasks like movement, transport, or control. This specialization is called division of labour and increases efficiency. Even though cells are specialized, they coordinate to keep the organism alive as one unit. The key difference is single-cell total functioning versus multi-cell specialization. Hence, this distinction best represents cellular organisation in living beings.
34. Which example best represents the idea of cellular organisation as a structural basis of life?
ⓐ. Melting of ice into water
ⓑ. Increase in crystal size by deposition from a solution
ⓒ. Formation of tissues from similar cells in multicellular organisms
ⓓ. Rusting of iron in moist air
Correct Answer: Formation of tissues from similar cells in multicellular organisms
Explanation: Tissues are formed when similar cells group together to perform a specific function. This shows that cells are arranged in an organized way to build higher structural levels. Such organization supports complex life functions like transport, protection, and movement. The formation of tissues demonstrates planned biological structure arising from cellular units. This arrangement is unique to living organisms and depends on cell coordination. Therefore, tissue formation is a clear example of cellular organisation.
35. Which statement best links cellular organisation to the functional unit concept?
ⓐ. Cells are present only in dead organisms and fossils.
ⓑ. Cells are the basic functional units that perform essential life processes within an organism.
ⓒ. Cells only provide color and shape but do not take part in life functions.
ⓓ. Cells form only after reproduction occurs.
Correct Answer: Cells are the basic functional units that perform essential life processes within an organism.
Explanation: A functional unit is the smallest part capable of carrying out essential processes. In living organisms, cells perform respiration, synthesis, transport, and regulation. Even in multicellular organisms, organs function because their cells perform cellular activities. Growth and repair happen through cell division and cellular work. Since life processes operate at the cellular level, cells are called the basic functional units. Hence, cellular organisation is foundational to life.
36. Which of the following best describes the hierarchy that results from cellular organisation in multicellular organisms?
ⓐ. Organs → Cells → Tissues → Organism → Organ systems
ⓑ. Cells → Tissues → Organs → Organ systems → Organism
ⓒ. Organ systems → Cells → Organs → Tissues → Organism
ⓓ. Tissues → Cells → Organ systems → Organs → Organism
Correct Answer: Cells → Tissues → Organs → Organ systems → Organism
Explanation: Multicellular organisms show levels of organisation starting from cells. Similar cells form tissues, and multiple tissues combine to form organs. Organs work together in organ systems to perform major body functions. All organ systems coordinate to form the complete organism. This hierarchy explains how complex structures develop from basic cellular units. Therefore, the correct sequence is cells to tissues to organs to organ systems to organism.
37. Why is cellular organisation considered a fundamental property of living beings?
ⓐ. Because it allows external growth by deposition like crystals.
ⓑ. Because it provides a structural framework necessary for coordinated life processes.
ⓒ. Because it prevents any response to environmental stimuli.
ⓓ. Because it ensures organisms never change with time.
Correct Answer: Because it provides a structural framework necessary for coordinated life processes.
Explanation: Life requires coordination of many processes like metabolism, transport, growth, and response. Cellular organisation provides the structured framework where these processes are controlled and integrated. Cells communicate and work together so the organism functions as one unit. In multicellular organisms, specialized cells and tissues cooperate for efficiency and survival. Without cellular structure, there would be no regulated life activities. Hence, cellular organisation is fundamental because it enables coordinated life processes.
38. Which concept best connects cellular organisation to efficiency in multicellular organisms?
ⓐ. External growth by surface deposition
ⓑ. Random mixing of tissues
ⓒ. Division of labour among specialized cells
ⓓ. Absence of internal control mechanisms
Correct Answer: Division of labour among specialized cells
Explanation: In multicellular organisms, different cells specialize for different functions, such as nerve cells for coordination or muscle cells for movement. Specialization improves efficiency because each cell type becomes adapted for its specific job. This division of labour is possible only when cells are organized and coordinated. It allows complex functions to occur simultaneously and effectively. Coordination among specialized cells maintains survival of the organism as a whole. Therefore, division of labour is the key efficiency link of cellular organisation.
39. Which statement correctly explains why non-living objects cannot be described as having cellular organisation?
ⓐ. Non-living objects always contain tissues and organs.
ⓑ. Non-living objects show regulated metabolic pathways.
ⓒ. Non-living objects are always capable of reproduction.
ⓓ. Non-living objects lack cells, so they do not have a structured functional unit system.
Correct Answer: Non-living objects lack cells, so they do not have a structured functional unit system.
Explanation: Cellular organisation requires cells that provide structure and perform life functions. Non-living objects do not have cells, membranes, organelles, or regulated internal systems. Without cells, there is no coordinated framework for metabolism, growth by cell division, repair, or response. Any changes in non-living matter are purely physical or chemical and not controlled for survival. Because cells are absent, the organized living hierarchy cannot exist. Therefore, non-living objects cannot show cellular organisation.
40. Which one is the most accurate conclusion about cellular organisation as a marker of life?
ⓐ. Cellular organisation supports the existence of life because life processes operate through cellular units.
ⓑ. Cellular organisation is optional and exists only in plants.
ⓒ. Cellular organisation occurs only when an organism is reproducing.
ⓓ. Cellular organisation is seen in crystals during growth.
Correct Answer: Cellular organisation supports the existence of life because life processes operate through cellular units.
Explanation: Life processes such as metabolism, regulation, growth, and response occur within cells. Even the simplest living organism shows life because its cell performs all necessary functions. In complex organisms, cells coordinate to form tissues and organs that perform specialized roles. This cellular framework ensures stability, control, and survival in varying conditions. Since cells are the base units where life operates, cellular organisation is central to living systems. Therefore, cellular organisation is a reliable marker distinguishing living from non-living.
41. In living organisms, “internal growth” mainly occurs due to which process?
ⓐ. Accumulation of dust particles
ⓑ. Deposition of minerals on the surface
ⓒ. Cooling and solidification of matter
ⓓ. Cell division increasing the number of cells
Correct Answer: Cell division increasing the number of cells
Explanation: Internal growth in living organisms happens by an increase in cell number through cell division. New cells are formed from pre-existing cells, leading to an increase in body mass and size from within. This growth is controlled and regulated by genetic and physiological mechanisms. It involves synthesis of new cellular material and organization into tissues. This is why living growth is considered intrinsic to the organism’s body plan. Hence, internal growth is fundamentally linked to cell division.
42. “External growth” is best described as which type of increase in size?
ⓐ. Increase in size by formation of new tissues
ⓑ. Increase in size by addition of material on the outer surface
ⓒ. Increase in size by multiplication of cells
ⓓ. Increase in size by development of organs
Correct Answer: Increase in size by addition of material on the outer surface
Explanation: External growth refers to an increase in size due to deposition of material from outside onto the surface. This does not involve formation of new cells or internal biological regulation. Such growth is commonly seen in non-living objects where matter accumulates externally. The structure increases in size, but there is no internal organization or life activity involved. This growth is purely physical and not a biological process. Therefore, external growth is defined by surface addition of material.
43. Which example most clearly shows external growth (non-living type growth)?
ⓐ. A seed developing into a seedling
ⓑ. A child increasing in height
ⓒ. A crystal increasing in size in a saturated solution
ⓓ. A plant producing new leaves
Correct Answer: A crystal increasing in size in a saturated solution
Explanation: A crystal grows by deposition of more molecules from the surrounding solution onto its surface. This increase happens externally and does not involve cell formation or internal regulation. The process is driven by physical conditions like concentration and temperature. There is no cellular organization, metabolism, or controlled biological development in this growth. Hence, crystal growth is a classic example of external growth. This makes it fundamentally different from growth in living organisms.
44. Which statement correctly distinguishes internal growth from external growth?
ⓐ. Internal growth occurs only in non-living things.
ⓑ. External growth requires cell division.
ⓒ. Internal growth is always faster than external growth.
ⓓ. Internal growth increases mass from within, while external growth increases size by surface deposition.
Correct Answer: Internal growth increases mass from within, while external growth increases size by surface deposition.
Explanation: Internal growth in living organisms happens through formation of new cellular material inside the body. It involves cell division, differentiation, and regulated development. External growth happens when material deposits on the surface from outside, without any living cellular activity. The key difference is the source and mechanism of increase—inside biological formation versus outside physical addition. This distinction is central to understanding why growth alone cannot define life. Therefore, internal growth is intrinsic, while external growth is surface-based deposition.
45. Why is “growth” not considered an absolute defining property of living beings?
ⓐ. Because only animals show growth
ⓑ. Because some non-living things also show increase in size
ⓒ. Because growth never occurs in plants
ⓓ. Because growth occurs only after reproduction
Correct Answer: Because some non-living things also show increase in size
Explanation: Growth is not an absolute defining property because non-living objects can also increase in size. For example, crystals can grow by external deposition of particles from a solution. This means the mere increase in size cannot be used to confirm that something is living. Living growth is internal and regulated, but the outward result “increase in size” can be seen in non-living systems too. Because the feature is not exclusive to living organisms, it cannot be an absolute defining criterion. Hence, growth alone is insufficient to define life.
46. Which feature best supports that growth in living organisms is an internal, organized process?
ⓐ. Formation of new cells leading to tissue development
ⓑ. Deposition of layers from outside
ⓒ. Increase in size by sediment accumulation
ⓓ. Surface coating by minerals
Correct Answer: Formation of new cells leading to tissue development
Explanation: Living growth involves production of new cells through cell division, followed by organization into tissues and organs. This process is regulated and follows a developmental plan, ensuring proper structure and function. The increase in size occurs from within the organism by adding living cellular material. Such growth supports repair, replacement, and development. Because it is organized, it results in functional complexity rather than just size increase. Therefore, new cell formation and tissue development best represent internal, living growth.
47. Which statement correctly represents how a crystal “grows”?
ⓐ. It grows by cell division inside the crystal
ⓑ. It grows by internal metabolic reactions
ⓒ. It grows by external accumulation of particles on its surface
ⓓ. It grows by forming tissues and organs
Correct Answer: It grows by external accumulation of particles on its surface
Explanation: Crystal growth happens when particles from the surrounding medium attach to the crystal surface. The process is governed by physical conditions such as concentration and temperature, not by biological control. There are no cells, enzymes, or internal regulatory mechanisms involved. The increase occurs as additional layers form externally, expanding the crystal’s size. This is a non-living type of growth because it lacks cellular organization. Hence, crystal growth is best explained as external accumulation on the surface.
48. In living organisms, which phrase best describes the nature of growth?
ⓐ. External and uncontrolled
ⓑ. Random and surface-based
ⓒ. Internally regulated and coordinated
ⓓ. Entirely dependent on mineral deposition
Correct Answer: Internally regulated and coordinated
Explanation: Growth in living organisms is controlled by internal biological mechanisms, including genes, hormones, and cellular regulation. It occurs through cell division, cell enlargement, and differentiation in a coordinated manner. This coordination ensures that body parts develop in correct proportion and function. The process is not random; it follows a structured developmental pattern. Because it is regulated, living growth supports proper organization and survival. Therefore, living growth is best described as internally regulated and coordinated.
49. Which observation most strongly indicates internal growth rather than external growth?
ⓐ. Increase in size due to dust settling on an object
ⓑ. Increase in mass due to deposition of salts on the surface
ⓒ. Increase in body size due to formation of new cells
ⓓ. Increase in thickness due to repeated coating
Correct Answer: Increase in body size due to formation of new cells
Explanation: Internal growth is characterized by the creation of new living material within the organism. Formation of new cells through cell division increases the organism’s mass and size from inside. This process is biologically controlled and contributes to development and repair. Unlike external coating or deposition, it produces functional, organized tissue. The key evidence is that new cells are being formed as part of the organism. Therefore, increase due to new cell formation indicates internal growth.
50. Which statement best captures the key contrast between living growth and non-living growth?
ⓐ. Living growth is always visible, non-living growth is always invisible
ⓑ. Living growth occurs only in water, non-living growth occurs only on land
ⓒ. Living growth is always reversible, non-living growth is never reversible
ⓓ. Living growth is internal (cell-based), while non-living growth is external (deposition-based)
Correct Answer: Living growth is internal (cell-based), while non-living growth is external (deposition-based)
Explanation: Living growth occurs through cellular processes such as cell division and formation of new internal material. This growth is regulated and results in organized development of tissues and organs. Non-living growth, as seen in crystals, occurs when particles accumulate externally on the surface. It does not involve cells, internal regulation, or biological organization. The core contrast lies in mechanism: cell-based internal increase versus deposition-based external increase. Hence, internal cell-based growth distinguishes living systems from non-living growth.
51. Which statement best describes “living growth” in organisms?
ⓐ. Increase in size only by surface deposition
ⓑ. Increase in size due to internal formation of new cellular material
ⓒ. Increase in size without any internal regulation
ⓓ. Increase in size only when placed in a saturated solution
Correct Answer: Increase in size due to internal formation of new cellular material
Explanation: Living growth occurs from within the organism by formation of new cells and cellular components. It is controlled by biological mechanisms such as cell division, differentiation, and regulation by genetic instructions. This type of growth produces organized tissues and increases the functional complexity of the body. The increase in size is not a simple physical addition but a biological construction process. It also supports repair and development in a planned manner. Therefore, living growth is best described as internal formation of new cellular material.
52. Crystal growth is mainly considered non-living growth because it occurs by which mechanism?
ⓐ. Cell division
ⓑ. Tissue differentiation
ⓒ. Internal metabolism
ⓓ. External deposition of material on the surface
Correct Answer: External deposition of material on the surface
Explanation: Crystal growth happens when particles from the surrounding solution attach to the outer surface of the crystal. This is a physical process driven by concentration and temperature conditions. There is no cellular organization, no enzymes, and no internal regulation guiding the growth. The crystal does not form tissues or develop functional complexity. The size increases only by adding layers externally. Hence, external deposition is the key reason crystal growth is considered non-living growth.
53. Which feature most clearly differentiates living growth from crystal growth?
ⓐ. Living growth is regulated and organized, while crystal growth is unregulated physical deposition.
ⓑ. Living growth always occurs in sunlight, while crystal growth occurs in darkness.
ⓒ. Living growth happens only in water, while crystal growth happens only on land.
ⓓ. Living growth is always faster, while crystal growth is always slower.
Correct Answer: Living growth is regulated and organized, while crystal growth is unregulated physical deposition.
Explanation: Living growth follows internal control mechanisms like genes and hormones, ensuring proper development of form and function. It involves coordinated cell division and differentiation, leading to organized tissues and organs. Crystal growth, however, is driven by physical conditions and occurs by deposition of particles on the surface without biological control. It does not create functional structures, only increases size. The key distinction is regulation and organization versus simple physical accumulation. Therefore, regulated organized growth differentiates living growth from crystal growth.
54. Which example best represents living growth?
ⓐ. A crystal enlarging in a sugar solution
ⓑ. A seedling increasing in height by cell division and enlargement
ⓒ. Salt crystals forming on a wet surface
ⓓ. Ice crystals increasing in size inside a freezer
Correct Answer: A seedling increasing in height by cell division and enlargement
Explanation: A seedling grows by biological processes such as cell division, cell enlargement, and differentiation. This growth is internally regulated and results in formation of tissues like roots, stems, and leaves. It increases both size and functional complexity of the organism. The process occurs within living cells using metabolic energy and genetic instructions. Unlike crystals, the seedling’s growth is not merely surface addition. Hence, a seedling increasing in height represents living growth.
55. Why can growth alone not be used as an absolute criterion to define living organisms?
ⓐ. Because living organisms do not grow after birth
ⓑ. Because growth occurs only in animals, not in plants
ⓒ. Because non-living objects like crystals can also increase in size
ⓓ. Because growth always requires reproduction
Correct Answer: Because non-living objects like crystals can also increase in size
Explanation: Growth is not an absolute defining feature because some non-living objects also show an increase in size. Crystals can grow by deposition of molecules from their environment, producing a visible increase in size. This shows that “increase in size” is not exclusive to living organisms. Living growth is internal and regulated, but the outward result can look similar to non-living growth. Therefore, growth alone cannot confirm whether something is living. Hence, the presence of crystal growth makes growth an insufficient defining criterion.
56. Which statement best explains the “internal” nature of living growth?
ⓐ. It occurs due to accumulation of particles from outside onto the surface.
ⓑ. It occurs due to formation and multiplication of cells within the body.
ⓒ. It occurs only when the organism is in a saturated solution.
ⓓ. It occurs without any biochemical activity.
Correct Answer: It occurs due to formation and multiplication of cells within the body.
Explanation: Living growth takes place through the formation of new cells inside the organism. This happens primarily by cell division, which increases cell number and contributes to body mass. The process is supported by metabolism, providing energy and building materials for new cellular components. It is regulated so that growth occurs in proper proportions and patterns. This internal formation distinguishes it from crystal growth, which is surface-based. Therefore, living growth is internal because it is based on cell formation and multiplication.
57. Which condition most directly supports crystal growth in a laboratory setting?
ⓐ. Presence of hormones regulating cell division
ⓑ. Presence of enzymes controlling pathways
ⓒ. A saturated solution that allows deposition on the crystal surface
ⓓ. Presence of tissues and organs for development
Correct Answer: A saturated solution that allows deposition on the crystal surface
Explanation: Crystal growth requires a medium containing dissolved particles that can deposit on the crystal surface. In a saturated solution, the concentration is high enough that particles readily attach to the existing crystal lattice. This deposition increases the crystal’s size externally. The process does not involve cellular regulation, enzymes, or metabolism. It depends mainly on physical conditions like temperature and concentration. Therefore, a saturated solution enabling deposition is the key condition for crystal growth.
58. Which of the following best captures why living growth is considered a biological process?
ⓐ. It increases size only by adding layers from outside.
ⓑ. It depends on cellular activity and is coordinated by internal regulation.
ⓒ. It occurs only when substances crystallize.
ⓓ. It happens without energy requirement.
Correct Answer: It depends on cellular activity and is coordinated by internal regulation.
Explanation: Living growth depends on cellular processes such as synthesis of biomolecules, cell division, and differentiation. These activities require energy and are regulated by internal control systems to maintain proper body structure. Growth is coordinated so that tissues form correctly and organs develop functional relationships. This biological control ensures organized development rather than random increase in size. Such coordination is possible only in living systems. Hence, living growth is considered a biological process due to its dependence on regulated cellular activity.
59. What is the most accurate outcome of living growth compared to crystal growth?
ⓐ. Living growth produces functional complexity, while crystal growth produces only increased size.
ⓑ. Living growth produces only increased size, while crystal growth produces tissues.
ⓒ. Living growth produces minerals, while crystal growth produces cells.
ⓓ. Living growth occurs only externally, while crystal growth occurs internally.
Correct Answer: Living growth produces functional complexity, while crystal growth produces only increased size.
Explanation: Living growth results in development of organized structures such as tissues and organs, increasing functional complexity. It supports repair, development, and specialization of body parts. Crystal growth only increases the physical size of the crystal by adding layers externally, without creating functional systems. There is no organization into higher biological levels in crystals. The key difference is that living growth builds complexity, while crystal growth only builds mass. Therefore, living growth produces functional complexity, unlike crystal growth.
60. Which statement correctly summarizes the difference between living growth and crystal growth?
ⓐ. Living growth is external and uncontrolled, while crystal growth is internal and regulated.
ⓑ. Living growth and crystal growth are identical processes.
ⓒ. Living growth occurs through cell division and differentiation, while crystal growth occurs through surface deposition.
ⓓ. Living growth does not require energy, while crystal growth requires energy.
Correct Answer: Living growth occurs through cell division and differentiation, while crystal growth occurs through surface deposition.
Explanation: Living growth involves multiplication of cells and their differentiation into tissues, guided by internal regulation. This produces organized development and functional structures. Crystal growth occurs when particles deposit on the surface of an existing crystal from a surrounding medium. It is governed by physical conditions and does not involve cellular processes. The key contrast lies in mechanism: biological internal construction versus physical external deposition. Therefore, living growth occurs through cell division and differentiation, while crystal growth occurs through surface deposition.
61. Why is reproduction considered “not a universal characteristic” of living organisms?
ⓐ. Because some living organisms never perform metabolic activities
ⓑ. Because some living organisms are sterile and cannot reproduce
ⓒ. Because all living organisms reproduce only once in their lifetime
ⓓ. Because reproduction occurs only in plants, not in animals
Correct Answer: Because some living organisms are sterile and cannot reproduce
Explanation: Reproduction is important for continuity of a species, but it is not present in every living individual. Some living organisms are naturally sterile or functionally sterile and therefore do not produce offspring. Despite not reproducing, they still carry out essential life processes like metabolism, growth, and response. A characteristic must be present in all living organisms to be considered universal. Since exceptions exist, reproduction cannot be treated as a universal defining property. Hence, sterility in some living organisms makes reproduction non-universal.
62. Which example best supports the idea that an organism can be living even if it cannot reproduce?
ⓐ. A crystal growing in a saturated solution
ⓑ. A mule that performs life processes but is sterile
ⓒ. A flame that uses oxygen and releases energy
ⓓ. A rock breaking down into smaller pieces
Correct Answer: A mule that performs life processes but is sterile
Explanation: A mule is produced by crossing a horse and a donkey, and it is commonly sterile. Even though it cannot reproduce, it performs all essential life activities such as respiration, digestion, circulation, and metabolism. This shows that reproduction is not required for an individual to be considered living. The living state depends on ongoing cellular and physiological processes, not on producing offspring. Therefore, the mule is a strong example supporting reproduction as non-universal. It proves that non-reproduction does not mean non-living.
63. Sterile worker bees are often cited as evidence that reproduction is not universal because they primarily perform which role?
ⓐ. Only producing eggs for the colony
ⓑ. Converting into queens during adulthood automatically
ⓒ. Forming crystals inside the hive
ⓓ. Carrying out colony maintenance and foraging without reproducing
Correct Answer: Carrying out colony maintenance and foraging without reproducing
Explanation: Sterile worker bees typically do not reproduce, yet they are fully living individuals. Their main role is to maintain the hive, collect nectar and pollen, protect the colony, and care for larvae. These activities show active life functions like movement, response, and metabolism. Their sterility is linked to social structure and division of labour in the colony. This demonstrates that a living organism may exist without reproductive ability. Hence, worker bees support the idea that reproduction is not universal.
64. What is the most accurate conclusion about reproduction as a criterion to define life?
ⓐ. Reproduction can be absent in some living organisms, so it cannot be the sole defining criterion.
ⓑ. Reproduction is present in all living individuals without exception.
ⓒ. Reproduction is more universal than metabolism.
ⓓ. Reproduction is the only feature that separates living from non-living.
Correct Answer: Reproduction can be absent in some living organisms, so it cannot be the sole defining criterion.
Explanation: A defining criterion must apply to every living organism without exception. Some living individuals, such as mules and sterile worker bees, do not reproduce due to biological or functional reasons. Even without reproduction, they show key life processes like metabolism, growth, and response. This proves reproduction cannot be used alone to define life. Reproduction remains important for species continuation, but not for identifying every living individual. Therefore, reproduction cannot be the sole defining criterion of life.
65. Which statement best explains the biological significance of reproduction despite it being non-universal?
ⓐ. Reproduction is responsible for crystal formation in nature.
ⓑ. Reproduction is the process that keeps an individual alive daily.
ⓒ. Reproduction directly replaces metabolism in living organisms.
ⓓ. Reproduction is essential for the continuity and survival of a species over generations.
Correct Answer: Reproduction is essential for the continuity and survival of a species over generations.
Explanation: Reproduction ensures that new individuals are produced to replace older ones, allowing a species to persist over time. It transfers genetic information from one generation to the next, helping maintain the species identity. Variation arising during reproduction also supports adaptation and evolution. Although some individuals may not reproduce, the species as a whole depends on reproduction for continuation. This is why reproduction is biologically significant even if not universal in all individuals. Hence, reproduction is vital for species continuity across generations.
66. Which of the following pairs correctly represents living organisms that may not reproduce?
ⓐ. Mules and sterile worker bees
ⓑ. Crystals and stones
ⓒ. Fire and water
ⓓ. Salt and sugar
Correct Answer: Mules and sterile worker bees
Explanation: Mules are usually sterile due to chromosomal mismatch from their parent species, so they cannot produce offspring. Sterile worker bees also typically do not reproduce because their role is non-reproductive within the colony structure. Despite this, both are living organisms that perform essential life processes. This demonstrates that reproduction is not present in every living individual. These examples are commonly used to show exceptions to the universality of reproduction. Therefore, mules and sterile worker bees are correct examples.
67. Which reason best explains sterility in mules?
ⓐ. Lack of cellular organization in body tissues
ⓑ. Chromosomal mismatch that prevents formation of functional gametes
ⓒ. Absence of metabolic activity in cells
ⓓ. Inability to respond to environmental stimuli
Correct Answer: Chromosomal mismatch that prevents formation of functional gametes
Explanation: A mule is a hybrid of a horse and a donkey, which have different chromosome numbers. This mismatch disrupts normal pairing of chromosomes during meiosis, making gamete formation defective. As a result, mules are typically sterile and cannot reproduce. However, the mule’s cells still function normally for life processes like respiration and growth. The key point is that sterility arises from genetic and chromosomal incompatibility, not from lack of life. Hence, chromosomal mismatch explains mule sterility.
68. In social insects like honeybees, which factor most directly explains why many workers do not reproduce?
ⓐ. Workers are non-living individuals
ⓑ. Workers lack metabolism and therefore cannot form gametes
ⓒ. Colony division of labour assigns reproduction mainly to the queen
ⓓ. Workers always transform into males before reproducing
Correct Answer: Colony division of labour assigns reproduction mainly to the queen
Explanation: Honeybee colonies show social organization where reproduction is largely the role of the queen. Worker bees are specialized for tasks such as foraging, nursing, and hive maintenance. This division of labour increases efficiency and survival of the colony as a whole. Worker sterility is part of this biological organization and is influenced by colony regulation mechanisms. Even though they do not reproduce, workers remain fully living and active. Therefore, division of labour assigning reproduction mainly to the queen explains worker non-reproduction.
69. Which statement best supports that reproduction is a species-level necessity rather than an individual-level necessity?
ⓐ. Individuals can remain living without reproducing, but the species cannot continue without reproduction.
ⓑ. Individuals cannot survive a day without reproducing.
ⓒ. Species survive by crystal growth instead of reproduction.
ⓓ. Reproduction is unrelated to continuation of life forms.
Correct Answer: Individuals can remain living without reproducing, but the species cannot continue without reproduction.
Explanation: A living individual can perform all life activities such as metabolism, growth, and response without reproducing. However, if no members of a species reproduce, the species will eventually disappear as individuals die. Reproduction ensures continuation of the species by producing new individuals. This shows reproduction is critical at the population and species level, even if not required for every individual. Therefore, reproduction is species-level necessity rather than individual-level necessity. Hence, individuals may be living without reproducing, but species survival depends on reproduction.
70. Which option best concludes the relationship between reproduction and defining life?
ⓐ. Reproduction is absent in all living organisms, so it cannot define life.
ⓑ. Reproduction is universal, so it alone defines life.
ⓒ. Reproduction occurs in many living organisms, but exceptions show it cannot be treated as a universal defining feature.
ⓓ. Reproduction is present only in non-living objects.
Correct Answer: Reproduction occurs in many living organisms, but exceptions show it cannot be treated as a universal defining feature.
Explanation: Reproduction is a common feature of living organisms and is essential for the continuation of species. However, some living individuals like mules and sterile worker bees do not reproduce. Because a defining feature must be present in all living organisms without exception, reproduction cannot be treated as universally defining. Living status is better confirmed using properties that are present in every living organism. Therefore, reproduction is important but not universal. Hence, it cannot be considered a universal defining feature of life.
71. Which statement best defines asexual reproduction?
ⓐ. Offspring are produced by fusion of male and female gametes.
ⓑ. Offspring are genetically identical to the parent in most cases.
ⓒ. Offspring are always produced only after meiosis.
ⓓ. Offspring are formed only in flowering plants.
Correct Answer: Offspring are genetically identical to the parent in most cases.
Explanation: Asexual reproduction involves a single parent producing offspring without the fusion of gametes. Since genetic material comes from only one parent, the offspring usually resemble the parent closely and are often called clones. This method is common in many unicellular organisms and some plants and animals. It enables rapid multiplication when conditions are favorable. Because it does not require mating, it is efficient in stable environments. Hence, genetic similarity to the parent is a key feature of asexual reproduction.
72. Which is the most accurate defining feature of sexual reproduction?
ⓐ. Formation of offspring from a single parent only
ⓑ. Offspring produced without any cell division
ⓒ. Production of offspring by fusion of gametes from two parents
ⓓ. Production of offspring only through budding
Correct Answer: Production of offspring by fusion of gametes from two parents
Explanation: Sexual reproduction involves two parents who contribute gametes—male and female. These gametes fuse during fertilization to form a zygote, which develops into a new organism. This process creates genetic variation because gametes are formed through meiosis and combine genetic material from both parents. Such variation improves adaptability and long-term survival of species. Sexual reproduction is common in most animals and many plants. Therefore, fusion of gametes from two parents is the defining feature.
73. Which of the following is an example of asexual reproduction in unicellular organisms?
ⓐ. Fertilization in humans
ⓑ. Fragmentation in starfish
ⓒ. Binary fission in Amoeba
ⓓ. Pollination in flowering plants
Correct Answer: Binary fission in Amoeba
Explanation: In binary fission, a unicellular organism divides into two nearly identical daughter cells. Amoeba reproduces by this method, where the nucleus divides first and then the cytoplasm splits. This process does not involve gamete formation or fertilization, so it is asexual reproduction. It allows rapid population increase in favorable conditions. Since the offspring are produced from one parent, genetic similarity is high. Hence, binary fission in Amoeba is a clear example of asexual reproduction.
74. Why does sexual reproduction generally produce more variation than asexual reproduction?
ⓐ. Because gamete fusion combines genetic material from two parents
ⓑ. Because it always produces identical offspring
ⓒ. Because it occurs without formation of gametes
ⓓ. Because it happens only in bacteria
Correct Answer: Because gamete fusion combines genetic material from two parents
Explanation: Sexual reproduction includes formation of gametes and their fusion during fertilization. Each gamete carries a unique genetic combination due to meiosis and recombination. When gametes from two parents unite, their genetic material mixes, creating new gene combinations in offspring. This increases variation within a population, which is beneficial for adaptation to changing environments. Variation is a major evolutionary advantage of sexual reproduction. Therefore, gamete fusion combining two parents’ genetic material explains higher variation.
75. Which pair correctly matches the reproduction type with the number of parents involved?
ⓐ. Asexual — two parents; Sexual — one parent
ⓑ. Asexual — one parent; Sexual — two parents
ⓒ. Asexual — three parents; Sexual — one parent
ⓓ. Asexual — no parent; Sexual — three parents
Correct Answer: Asexual — one parent; Sexual — two parents
Explanation: Asexual reproduction occurs when a single parent produces offspring without gamete fusion. In contrast, sexual reproduction typically requires two parents who contribute male and female gametes. The involvement of two parents allows genetic mixing and variation in sexual reproduction. Asexual reproduction is simpler and faster because it depends on one parent only. This difference in parental involvement is a fundamental way to classify reproductive types. Hence, asexual involves one parent, while sexual involves two parents.
76. Which of the following is most likely to be an advantage of asexual reproduction?
ⓐ. Rapid multiplication without the need to find a mate
ⓑ. Offspring always require two parents
ⓒ. Formation of gametes by meiosis is essential
ⓓ. High genetic variation in every generation
Correct Answer: Rapid multiplication without the need to find a mate
Explanation: Asexual reproduction allows organisms to reproduce quickly because only one parent is needed. There is no requirement for mating, gamete formation, or fertilization, so the process is efficient and time-saving. This can be especially beneficial in stable environments where the parent is already well adapted. Rapid multiplication helps organisms colonize habitats quickly when conditions are favorable. Because the process is straightforward, energy and time costs are lower. Therefore, rapid reproduction without needing a mate is a key advantage.
77. Which reproductive method involves formation of a zygote?
ⓐ. Binary fission
ⓑ. Budding
ⓒ. Fertilization in sexual reproduction
ⓓ. Fragmentation
Correct Answer: Fertilization in sexual reproduction
Explanation: A zygote is formed when male and female gametes fuse during fertilization. This is a defining step of sexual reproduction and marks the beginning of development of a new individual. Asexual methods like binary fission, budding, and fragmentation do not involve gametes and therefore do not produce a zygote. The zygote contains genetic material from both parents, enabling variation. It then undergoes further divisions to form the organism. Hence, zygote formation occurs during fertilization in sexual reproduction.
78. Which statement best describes the role of gametes in sexual reproduction?
ⓐ. Gametes are formed and fused to combine genetic material and start development.
ⓑ. Gametes are deposited externally to increase crystal size.
ⓒ. Gametes prevent cell division in the organism.
ⓓ. Gametes are produced only in unicellular organisms.
Correct Answer: Gametes are formed and fused to combine genetic material and start development.
Explanation: Gametes are specialized reproductive cells produced by male and female parents. In sexual reproduction, these gametes fuse during fertilization to form a zygote. The zygote carries combined genetic information and develops into a new organism. This fusion introduces genetic variation and supports long-term adaptability of populations. Gametes therefore serve as carriers and mixers of genetic material. Hence, gamete formation and fusion is central to sexual reproduction.
79. In which situation is asexual reproduction generally more common and successful?
ⓐ. In stable environments where rapid population increase is beneficial
ⓑ. In environments that change rapidly where variation is always required
ⓒ. Only in large mammals with long life spans
ⓓ. Only in organisms that cannot divide cells
Correct Answer: In stable environments where rapid population increase is beneficial
Explanation: Asexual reproduction produces offspring similar to the parent, which is advantageous when the environment remains stable and the parent is well adapted. It allows quick multiplication and efficient use of resources because only one parent is needed. In such conditions, producing many similar offspring helps expand population rapidly. Since there is limited variation, it is less suited to rapidly changing environments. Therefore, stable environments favor asexual reproduction. Hence, it is generally more common and successful in stable conditions.
80. Which statement most accurately summarizes asexual and sexual reproduction?
ⓐ. Asexual reproduction involves gamete fusion, while sexual reproduction does not.
ⓑ. Asexual reproduction produces variation, while sexual reproduction produces identical offspring.
ⓒ. Asexual reproduction needs two parents, while sexual reproduction needs one parent.
ⓓ. Asexual reproduction involves one parent without gamete fusion, while sexual reproduction involves gamete fusion and usually two parents.
Correct Answer: Asexual reproduction involves one parent without gamete fusion, while sexual reproduction involves gamete fusion and usually two parents.
Explanation: Asexual reproduction occurs when one parent produces offspring without formation and fusion of gametes. This generally results in offspring genetically similar to the parent. Sexual reproduction involves production of gametes and their fusion to form a zygote, usually requiring two parents. This mixing of genetic material leads to variation in offspring. The key difference is presence or absence of gamete fusion and number of parents involved. Therefore, this statement correctly summarizes both reproduction types.
81. Which statement best describes anabolism in metabolism?
ⓐ. It involves the breakdown of complex molecules to release energy.
ⓑ. It involves the formation of complex molecules from simpler molecules.
ⓒ. It occurs only outside living cells.
ⓓ. It produces only waste products without any synthesis.
Correct Answer: It involves the formation of complex molecules from simpler molecules.
Explanation: Anabolism is the constructive phase of metabolism where small molecules are combined to form larger, more complex molecules. This process is essential for growth, repair, and building cell structures such as proteins, nucleic acids, and membranes. Anabolic reactions usually require energy input because making bonds between molecules needs energy. These reactions occur in living cells under enzyme control. Anabolism supports the development and maintenance of the organism’s body. Therefore, anabolism is correctly described as the formation of complex molecules from simpler ones.
82. What is the primary role of catabolism in a living organism?
ⓐ. Building proteins from amino acids for growth
ⓑ. Forming DNA from nucleotides
ⓒ. Producing complex molecules for storage
ⓓ. Breaking down complex molecules to release usable energy
Correct Answer: Breaking down complex molecules to release usable energy
Explanation: Catabolism is the degradative phase of metabolism in which complex molecules like carbohydrates, fats, and proteins are broken down into simpler substances. During this breakdown, energy stored in chemical bonds is released and captured in usable forms like ATP. This energy powers essential life processes such as movement, transport, and synthesis. Catabolic reactions are continuous and necessary for maintaining cellular activity. They occur under enzyme control within cells. Hence, the primary role of catabolism is to break down complex molecules and release energy.
83. Which pair correctly matches the metabolic type with its general function?
ⓐ. Anabolism — breakdown; Catabolism — synthesis
ⓑ. Anabolism — synthesis; Catabolism — breakdown
ⓒ. Anabolism — excretion; Catabolism — reproduction
ⓓ. Anabolism — breathing; Catabolism — pollination
Correct Answer: Anabolism — synthesis; Catabolism — breakdown
Explanation: Anabolism refers to building up complex molecules from simpler ones, supporting growth and repair. Catabolism refers to breaking down complex molecules into simpler ones, releasing energy needed for life activities. These two processes are complementary and together make up metabolism. The balance between them helps maintain the body’s structure and energy needs. Both occur continuously in living cells. Therefore, anabolism is synthesis and catabolism is breakdown.
84. Which statement best explains why both anabolism and catabolism are essential?
ⓐ. Only anabolism is needed because organisms only build molecules.
ⓑ. Only catabolism is needed because organisms only break molecules.
ⓒ. Anabolism and catabolism occur only during reproduction.
ⓓ. Organisms need energy release from catabolism and energy use in anabolism for growth and maintenance.
Correct Answer: Organisms need energy release from catabolism and energy use in anabolism for growth and maintenance.
Explanation: Living organisms must both obtain energy and build/maintain their body structures. Catabolism releases energy by breaking down molecules, providing ATP and materials for cellular work. Anabolism uses that energy to synthesize complex molecules needed for growth, repair, and cell maintenance. Without catabolism, there would be no energy supply; without anabolism, the organism could not build essential biomolecules. Together, they maintain life balance and functioning. Hence, both are essential because catabolism supplies energy and anabolism uses it for construction.
85. Which process is most directly an example of anabolism?
ⓐ. Breakdown of glucose during respiration
ⓑ. Digestion of proteins into amino acids
ⓒ. Synthesis of proteins from amino acids
ⓓ. Breakdown of fats into fatty acids
Correct Answer: Synthesis of proteins from amino acids
Explanation: Protein synthesis involves joining amino acids to form large protein molecules, which is a building-up process. Such construction of complex biomolecules from simpler units is the key feature of anabolism. It requires energy and enzyme control inside cells. Proteins formed are essential for structure, enzymes, transport, and regulation. This process supports growth and repair in organisms. Therefore, protein synthesis from amino acids is a direct example of anabolism.
86. Which of the following is most clearly a catabolic activity?
ⓐ. Formation of glycogen from glucose
ⓑ. Formation of DNA from nucleotides
ⓒ. Breakdown of glycogen into glucose for energy
ⓓ. Formation of lipids from fatty acids and glycerol
Correct Answer: Breakdown of glycogen into glucose for energy
Explanation: Catabolism involves breaking down stored or complex molecules to release energy or provide simpler substances. Glycogen is a stored polysaccharide that can be broken down into glucose when energy is needed. This breakdown releases glucose, which then enters pathways to produce ATP. The process is controlled and occurs within living cells. It supports immediate energy demands during activity or fasting. Hence, breakdown of glycogen into glucose is a clear catabolic activity.
87. How are anabolism and catabolism related in metabolism?
ⓐ. They are unrelated processes occurring in different organisms only.
ⓑ. They work together, where catabolism provides energy and building blocks for anabolic synthesis.
ⓒ. Anabolism destroys molecules while catabolism builds new ones.
ⓓ. They occur only in plants, not in animals.
Correct Answer: They work together, where catabolism provides energy and building blocks for anabolic synthesis.
Explanation: Catabolism breaks down molecules to release energy and produce simpler intermediates. These intermediates and the released energy are then used in anabolic reactions to build complex molecules. This coupling ensures that cells have both energy and materials required for growth and maintenance. Metabolism is balanced by these two opposite but interconnected processes. Continuous coordination between them maintains stability of the organism. Therefore, anabolism and catabolism work together, with catabolism supporting anabolism through energy and raw materials.
88. Which statement best describes energy flow in anabolism versus catabolism?
ⓐ. Both anabolism and catabolism always consume energy only.
ⓑ. Both anabolism and catabolism always release energy only.
ⓒ. Anabolism releases energy, while catabolism consumes energy.
ⓓ. Anabolism generally consumes energy, while catabolism generally releases energy.
Correct Answer: Anabolism generally consumes energy, while catabolism generally releases energy.
Explanation: Anabolic reactions build complex molecules, which usually requires an input of energy to form chemical bonds. Catabolic reactions break down complex molecules and release energy stored in those bonds. The released energy is often captured in ATP and then used for anabolic and other cellular activities. This energy coupling is essential for sustaining life processes. Cells continuously balance these reactions to meet both energy and structural needs. Hence, anabolism consumes energy while catabolism releases energy.
89. Which example best represents a catabolic pathway that helps cells produce ATP?
ⓐ. Photosynthetic glucose formation
ⓑ. Protein synthesis on ribosomes
ⓒ. Breakdown of glucose in cellular respiration
ⓓ. Formation of starch in plants
Correct Answer: Breakdown of glucose in cellular respiration
Explanation: Cellular respiration involves breaking down glucose into simpler molecules like carbon dioxide and water. During this process, energy stored in glucose is released and captured as ATP, which powers cellular activities. This is a classic catabolic pathway because it breaks down a complex molecule for energy. The reactions occur in a regulated series inside cells. ATP produced supports movement, transport, and synthesis. Therefore, breakdown of glucose in cellular respiration is a clear catabolic pathway producing ATP.
90. Which conclusion best summarizes anabolism and catabolism as parts of metabolism?
ⓐ. Anabolism and catabolism are separate from metabolism and do not affect life processes.
ⓑ. Anabolism builds complex molecules, catabolism breaks them down, and together they maintain life functions.
ⓒ. Anabolism is only for plants and catabolism is only for animals.
ⓓ. Anabolism and catabolism occur only during growth stages.
Correct Answer: Anabolism builds complex molecules, catabolism breaks them down, and together they maintain life functions.
Explanation: Metabolism includes both building and breaking processes that operate continuously in living organisms. Anabolism forms complex biomolecules needed for structure and function, supporting growth and repair. Catabolism breaks down molecules to release energy and provide materials for cellular activities. Together, these processes keep the organism alive by balancing energy needs and structural maintenance. The coordination between them ensures stable functioning under changing conditions. Hence, anabolism and catabolism together maintain life functions as key parts of metabolism.
91. What is the most accurate meaning of “cellular reactions” in the context of metabolism?
ⓐ. Only physical changes happening outside the body
ⓑ. All chemical reactions occurring within living cells
ⓒ. Only reactions that occur during reproduction
ⓓ. Only reactions that involve movement of the organism
Correct Answer: All chemical reactions occurring within living cells
Explanation: Cellular reactions refer to the chemical reactions that take place inside living cells. These reactions include building molecules, breaking down nutrients, producing energy, and maintaining internal balance. They are controlled by enzymes and occur in an organized sequence rather than randomly. Such reactions are essential for survival because they support growth, repair, and regulation. Since these reactions happen within cells, they reflect active cellular functioning. Therefore, cellular reactions mean all chemical reactions occurring within living cells.
92. Which statement best explains why metabolic cellular reactions are considered highly organized?
ⓐ. They occur randomly without any control.
ⓑ. They occur only at the body surface.
ⓒ. They are controlled by enzymes and follow specific pathways.
ⓓ. They happen only when an organism moves.
Correct Answer: They are controlled by enzymes and follow specific pathways.
Explanation: Metabolic reactions inside cells are arranged into pathways where one reaction leads to the next. Enzymes control each step, ensuring reactions occur at correct rates and in proper directions. This organization prevents harmful side reactions and increases efficiency. Cellular compartments also help regulate where reactions occur. Such coordination is essential to maintain homeostasis and survival. Hence, metabolic cellular reactions are highly organized due to enzyme control and pathway structure.
93. Which component directly speeds up cellular metabolic reactions without being consumed?
ⓐ. Enzymes
ⓑ. Dust particles
ⓒ. Minerals
ⓓ. Water droplets
Correct Answer: Enzymes
Explanation: Enzymes are biological catalysts that increase the rate of chemical reactions in cells. They lower the activation energy required, allowing reactions to occur quickly at normal body temperature. Enzymes are highly specific, meaning each enzyme acts on particular substrates. They are not used up in the reaction and can be reused multiple times. Without enzymes, many vital cellular reactions would be too slow to sustain life. Therefore, enzymes directly speed up metabolic reactions without being consumed.
94. Which statement best supports that cellular reactions are essential for maintaining life?
ⓐ. Cellular reactions are optional and occur only in some cells.
ⓑ. Cellular reactions occur only in dead tissues.
ⓒ. Cellular reactions help produce energy and build necessary biomolecules.
ⓓ. Cellular reactions happen only in the presence of sunlight.
Correct Answer: Cellular reactions help produce energy and build necessary biomolecules.
Explanation: Cellular reactions include processes that release energy from nutrients and processes that synthesize essential molecules like proteins and DNA. Energy production supports activities such as transport, repair, and regulation. Synthesis reactions build structures required for growth and maintenance of cells. These reactions occur continuously to keep the organism alive and stable. Without them, cells cannot maintain internal balance or function. Hence, cellular reactions are essential because they produce energy and build biomolecules.
95. Where do most cellular metabolic reactions occur in a living organism?
ⓐ. Inside living cells
ⓑ. Only in the external environment
ⓒ. Only in bones
ⓓ. Only in hair and nails
Correct Answer: Inside living cells
Explanation: Metabolic reactions are the chemical activities that keep an organism alive, and they occur within living cells. Cells contain enzymes, substrates, and organized structures that allow reactions to proceed efficiently. Even in multicellular organisms, organs function because their cells perform these reactions. Different cell parts, such as cytoplasm and organelles, support specific reaction types. Since the cell is the basic unit of life, it is also the site of metabolism. Therefore, most cellular metabolic reactions occur inside living cells.
96. Which example best represents a “cellular reaction” related to energy release?
ⓐ. Formation of proteins from amino acids
ⓑ. Breakdown of glucose during respiration
ⓒ. Formation of starch from glucose
ⓓ. Formation of DNA from nucleotides
Correct Answer: Breakdown of glucose during respiration
Explanation: Respiration involves breaking down glucose through a series of enzyme-controlled reactions. These reactions release energy that is captured in ATP, the usable energy currency of the cell. This ATP is then used to power other cellular activities such as transport and synthesis. The breakdown is a cellular reaction because it occurs within cells and follows a metabolic pathway. It is essential for providing continuous energy supply. Therefore, glucose breakdown during respiration is a clear example of a cellular reaction for energy release.
97. Which statement best describes the relationship between cellular reactions and homeostasis?
ⓐ. Cellular reactions disturb internal balance and cause instability.
ⓑ. Cellular reactions help maintain stable internal conditions by regulating materials and energy.
ⓒ. Cellular reactions occur only when organisms are sleeping.
ⓓ. Cellular reactions are unrelated to internal regulation.
Correct Answer: Cellular reactions help maintain stable internal conditions by regulating materials and energy.
Explanation: Homeostasis means maintaining stable internal conditions like temperature, pH, and nutrient levels. Cellular reactions regulate how energy is produced and used and how substances are synthesized or broken down. This regulation ensures cells get required materials and remove wastes efficiently. Enzyme activity and feedback control adjust reaction rates based on the body’s needs. Such continuous adjustments maintain internal stability. Hence, cellular reactions support homeostasis by regulating energy and materials.
98. What is the primary reason cellular reactions are considered a strong marker of living systems?
ⓐ. They occur only in crystals and minerals.
ⓑ. They occur only when an organism reproduces.
ⓒ. They occur only in sunlight.
ⓓ. They occur continuously within living cells to sustain life processes.
Correct Answer: They occur continuously within living cells to sustain life processes.
Explanation: Cellular reactions are a strong marker of life because they reflect ongoing internal biochemical activity. These reactions support essential functions such as energy production, repair, growth, and regulation. They occur continuously as long as the cells are alive. Non-living objects may undergo chemical changes, but they do not show coordinated, enzyme-controlled pathways within cells. Continuous cellular reactions indicate active living processes. Therefore, continuous life-sustaining reactions within cells make cellular reactions a strong marker of living systems.
99. Which phrase best describes cellular reactions as compared to ordinary chemical reactions in non-living matter?
ⓐ. Cellular reactions are uncontrolled and random.
ⓑ. Cellular reactions are enzyme-controlled and occur in organized pathways.
ⓒ. Cellular reactions occur only in open air.
ⓓ. Cellular reactions do not involve any energy changes.
Correct Answer: Cellular reactions are enzyme-controlled and occur in organized pathways.
Explanation: Cellular reactions are part of metabolism and are controlled by enzymes, making them specific and regulated. They are arranged in pathways where products of one step become substrates for the next. This ensures efficiency and proper control of energy and material flow. In non-living matter, chemical reactions generally lack such biological regulation and integration. The organized nature of cellular reactions supports stable functioning of the organism. Hence, cellular reactions are best described as enzyme-controlled and pathway-based.
100. Which conclusion best summarizes the importance of cellular reactions in metabolism?
ⓐ. Cellular reactions are not necessary because organisms can survive without them.
ⓑ. Cellular reactions occur only in one organ of the body.
ⓒ. Cellular reactions are the basis of metabolism and support energy production and biosynthesis in living cells.
ⓓ. Cellular reactions are only physical changes and have no role in life.
Correct Answer: Cellular reactions are the basis of metabolism and support energy production and biosynthesis in living cells.
Explanation: Metabolism is made up of numerous cellular reactions that build and break molecules. These reactions provide energy through breakdown processes and create essential biomolecules through synthesis processes. They occur inside cells under enzyme control, ensuring regulation and efficiency. This cellular activity supports growth, repair, and maintenance of internal balance. Without these reactions, cells cannot function and life cannot continue. Therefore, cellular reactions form the basis of metabolism by supporting energy production and biosynthesis.