401. A multicellular eukaryote with a wall digests food outside its body and absorbs the products. It differs from a typical animal chiefly in:
ⓐ. a cell wall and absorptive feeding
ⓑ. presence of mitochondria for aerobic respiration
ⓒ. dependence on organic compounds
ⓓ. ability to reproduce sexually
Correct Answer: a cell wall and absorptive feeding
Explanation: The described organism shows the fungal pattern: a wall surrounds its cells, and digestion occurs externally before soluble nutrients are absorbed. Animals also depend on organic food but generally lack cell walls and ingest food for internal digestion. Mitochondria and sexual reproduction occur in both kingdoms and cannot provide the main contrast. The useful distinction combines cellular structure with the route of food acquisition. This prevents all heterotrophic eukaryotes from being treated as members of one kingdom. External digestion and wall presence fit the fungal pattern, while animals generally ingest food and lack walls.
402. An organism is multicellular and heterotrophic but has cellulose-rich walls and lacks ingestive feeding. The evidence is insufficient for Animalia mainly because:
ⓐ. animals are exclusively unicellular organisms
ⓑ. animals are photosynthetic multicellular organisms
ⓒ. animal heterotrophy excludes ingestion of food
ⓓ. animal cells characteristically lack cell walls
Correct Answer: animal cells characteristically lack cell walls
Explanation: Multicellularity and heterotrophy occur in animals, but they are not sufficient when another major character conflicts with the animal profile. Animal cells characteristically lack walls, whereas the specimen has cellulose-rich walls. Its feeding pattern also does not show the usual animal process of ingestion followed by internal digestion. Classification requires agreement among several criteria rather than selection of whichever two traits happen to match. The wall condition supplies a particularly strong reason to reject Animalia under the evidence given. Multicellularity and heterotrophy are shared with animals, but cellulose walls and non-ingestive feeding contradict the animal profile.
403. Consider the following statements about Kingdom Animalia.
I. Members are multicellular eukaryotes.
II. Cell walls are absent.
III. Food is generally ingested and digested internally.
IV. Starch is the principal reserve carbohydrate.
ⓐ. I and IV only
ⓑ. I, II and III only
ⓒ. II, III and IV only
ⓓ. I, II, III and IV
Correct Answer: I, II and III only
Explanation: Animalia includes multicellular eukaryotes lacking cell walls, making the first two statements valid. Their heterotrophic nutrition generally involves ingestion followed by internal digestion, so the third statement is also correct. Animals commonly store carbohydrate as glycogen rather than starch, which is associated more strongly with plants. The fourth statement is invalid. The accepted combination integrates cellular organisation, external boundary, and nutritional mechanism while excluding an incorrect reserve-food association. Statement IV is false because photosynthetic food production and cellulose walls are not general animal features. The valid set combines cell type, body organisation, wall absence, and the usual feeding mechanism.
404. Two organisms are compared below.
| Organism | Cell wall | Food acquisition | Reserve material |
|---|
| P | Absent | Ingestion and internal digestion | Glycogen and fat |
| Q | Present | External digestion and absorption | Not specified |
The most defensible interpretation is:
ⓐ. P is animal-like, whereas Q is fungus-like
ⓑ. P is plant-like, whereas Q is animal-like
ⓒ. both P and Q must be members of Animalia
ⓓ. both P and Q must be members of Fungi
Correct Answer: P is animal-like, whereas Q is fungus-like
Explanation: Organism P combines three animal characters: absence of a cell wall, ingestion followed by internal digestion, and storage of glycogen and fat. Organism Q has a wall and digests food externally before absorbing the soluble products, matching the general fungal pattern. Both organisms may be multicellular eukaryotic heterotrophs, so those broad similarities alone cannot separate them. The decisive table entries are the cellular boundary and the route of food acquisition. Reading all columns together identifies P as animal-like and Q as fungus-like without relying on one shared feature such as heterotrophy.
405. An animal is prevented from ingesting food, although its digestive enzymes remain functional inside the gut. The most immediate nutritional consequence is:
ⓐ. internal enzymes digest food normally without ingestion
ⓑ. the animal switches to external absorption through its body surface
ⓒ. less ingested food reaches the gut for internal digestion
ⓓ. stored glycogen completely replaces incoming food
Correct Answer: less ingested food reaches the gut for internal digestion
Explanation: Animal nutrition normally begins with ingestion, which delivers food into the digestive tract. If ingestion is prevented, enzymes inside the gut may remain active but receive little or no newly supplied substrate, so internal digestion soon declines. The defect occurs before enzymatic breakdown and does not alter the animal's kingdom identity, reserve carbohydrate, or cell-wall condition. It also cannot create photosynthetic organelles or fungal hyphae. The case separates possession of digestive machinery from access to food: functional enzymes cannot maintain normal nutrition when the material they act on fails to enter the body.
406. Animals commonly differ from continuously growing plant bodies in that adult animals tend to:
ⓐ. remain permanently unicellular throughout life
ⓑ. lose all capacity for tissue repair after maturity
ⓒ. acquire photosynthetic nutrition during adulthood
ⓓ. attain a relatively definite adult shape and size
Correct Answer: attain a relatively definite adult shape and size
Explanation: Animal growth usually follows a recognisable developmental pattern leading to an adult with a comparatively definite body form and size. This does not mean that every individual reaches an identical measurement or that growth and repair stop completely after maturity. The statement describes a broad organisational tendency. Animals remain multicellular heterotrophs and do not acquire photosynthesis during development. Definite adult form is one component of the animal profile and becomes especially meaningful when combined with coordinated organ systems and embryological development. Coordinated development produces an adult body plan with a characteristic form rather than indefinite addition of new organs.
407. A developing animal gradually acquires the body arrangement characteristic of its adult form. This observation best illustrates:
ⓐ. regulated growth toward a definite adult organisation
ⓑ. adult form develops without regulated growth
ⓒ. body organisation remains indefinite throughout life
ⓓ. development changes cell number but not body arrangement
Correct Answer: regulated growth toward a definite adult organisation
Explanation: Animal development involves coordinated changes in cell number, cell specialisation, tissue arrangement, and organ formation. As these processes proceed, the young organism approaches the characteristic shape and size of its adult body plan. The observation describes more than an increase in mass; it shows regulated growth toward a definite organisation. The cells remain eukaryotic throughout, and the process does not resemble indefinite production of new plant organs. A predictable adult arrangement is evidence of developmental control, not random or permanently undirected enlargement. The definite pattern emerges through differentiation and coordinated morphogenesis rather than through unrestricted addition of similar cells.
408. In higher animals, sensory and neuromotor mechanisms work together mainly to:
ⓐ. synthesise cellulose-rich external cell walls
ⓑ. detect stimuli and coordinate motor responses
ⓒ. perform chloroplast-based photosynthesis
ⓓ. absorb digested nutrients across fungal hyphae
Correct Answer: detect stimuli and coordinate motor responses
Explanation: Sensory mechanisms detect changes in the external environment or within the body. Neuromotor mechanisms transmit and integrate that information, then coordinate muscles and other effectors to produce an appropriate response. Their combined action supports movement, behaviour, posture, and rapid adjustment of body functions in higher animals. Detection alone would be incomplete without an organised motor output, while muscle activity without sensory and neural coordination would be poorly directed. Cellulose production, photosynthesis, and absorption across a mycelium belong to plant or fungal biology rather than animal sensory-motor integration. Coordination links perception with action, allowing the animal to select and execute a response suited to the detected stimulus.
409. Damage to sensory receptors while motor structures remain intact would most directly reduce an animal's ability to:
ⓐ. store glycogen and fat as reserve materials
ⓑ. digest ingested food through chemical enzymes
ⓒ. accurately detect changes in the environment
ⓓ. maintain the eukaryotic organisation of cells
Correct Answer: accurately detect changes in the environment
Explanation: Sensory receptors provide the input that informs an animal about light, chemicals, touch, temperature, and other conditions. Motor structures may remain capable of contraction or movement, but their responses become less appropriately guided when sensory information is lost. The damage does not directly remove glycogen storage, digestive enzymes, or eukaryotic organisation. The case distinguishes the ability to execute movement from the ability to detect the stimulus that should initiate or direct it. Motor components could still act, but the system would receive poorer information about the stimulus requiring a response.
410. The statement that most animals are capable of locomotion should be interpreted to mean that:
ⓐ. locomotion is common although some adult forms are sessile
ⓑ. every animal moves continuously throughout life
ⓒ. immobility automatically excludes an organism from Animalia
ⓓ. locomotion alone is sufficient for kingdom placement
Correct Answer: locomotion is common although some adult forms are sessile
Explanation: Most animals can change location during at least one stage of life, often through coordinated muscular and nervous activity. The qualifier most prevents the statement from becoming an absolute rule, since some adult animals are attached or show very limited locomotion even though earlier stages or body parts may move. Locomotion is a common supporting character, not a universal requirement or a sufficient basis for kingdom placement. Multicellular eukaryotic organisation, absence of a cell wall, ingestive heterotrophy, and developmental features must also agree with an animal identity. An attached adult can still belong to Animalia when the full cellular, nutritional, and developmental profile supports that placement.
411. A higher animal has functioning muscles but defective neuromotor coordination. The most likely result is:
ⓐ. failure of all muscle contraction
ⓑ. uncoordinated muscular movement
ⓒ. improved sensory detection
ⓓ. slower but coordinated movement
Correct Answer: uncoordinated muscular movement
Explanation: Muscles generate force, but neuromotor systems organise the timing, sequence, direction, and intensity of contractions. When coordination is defective, individual muscles may still contract, yet the contractions fail to combine into smooth and purposeful movement. The predicted result is impaired organisation of locomotion rather than complete absence of muscular activity. The defect does not change the organism's eukaryotic nature, nutritional mode, or lack of a cellulose wall. The case illustrates a component-system relation: effective movement requires both force-producing tissues and neural control that integrates their actions. Normal locomotion depends on integration of separate contractions into a spatially and temporally ordered pattern.
412. In the general animal life pattern, sexual reproduction is followed by:
ⓐ. sporangium formation
ⓑ. development of a fungal dikaryon
ⓒ. production of a plant gametophyte directly
ⓓ. embryological development
Correct Answer: embryological development
Explanation: Fusion of animal gametes produces a zygotic starting cell that undergoes ordered embryological development. Cell division, differentiation, and organisation gradually establish the body plan of the new individual. Sporangia and dikaryons belong to fungal life cycles, while a plant gametophyte develops within alternation of generations rather than directly representing the general animal sequence. The important relation is not sexual reproduction alone but its continuation into an embryo that develops through coordinated stages. The zygote undergoes ordered cell division and differentiation to produce the developing multicellular body. This developmental sequence converts the single-celled starting stage into an organised animal embryo.
413. A proposed sixth kingdom contains only viruses. The main reason this does not match Whittaker's normal five-kingdom placement is that viruses are:
ⓐ. multicellular heterotrophs with tissue-level organisation
ⓑ. unicellular eukaryotes with independent metabolism
ⓒ. acellular infectious agents lacking cellular organisation
ⓓ. photosynthetic prokaryotes with cellular organisation
Correct Answer: acellular infectious agents lacking cellular organisation
Explanation: Whittaker's kingdoms classify cellular organisms using features such as cell type, organisation, nutrition, and reproduction. Viruses are non-cellular particles composed of genetic material and protein rather than complete cells. Their replication also requires a suitable host cell. These properties place them outside the normal cellular framework of the five kingdoms. Describing them as a sixth kingdom would incorrectly treat an acellular agent as equivalent to cellular kingdoms without resolving the fundamental difference in organisation. Kingdom categories assume cellular organisation, whereas a virus lacks cytoplasm, ribosomes, and independent metabolism. Host-dependent replication does not convert the particle into an independently living cell.
414. Viroids and prions are excluded from ordinary five-kingdom placement mainly because they:
ⓐ. are larger than multicellular organisms
ⓑ. are acellular infectious agents
ⓒ. possess complete prokaryotic cells
ⓓ. form tissues but lack organs
Correct Answer: are acellular infectious agents
Explanation: Viroids consist of small infectious RNA molecules without a protein coat, while prions are infectious abnormal proteins. Neither possesses the complete cellular organisation required for normal placement in Monera, Protista, Fungi, Plantae, or Animalia. Their infectious capacity does not make them cellular organisms. The exclusion arises from the organisational boundary underlying the five-kingdom system, not from body size or absence of organs. They require separate treatment because their composition and mode of multiplication differ fundamentally from those of cells. Their infectivity does not supply the complete cell structure required for placement among cellular kingdoms.
415. Lichens are not assigned an independent kingdom in Whittaker's system because a lichen is:
ⓐ. a non-cellular infectious particle made only of protein
ⓑ. a prokaryotic colony with one shared nutritional mode
ⓒ. a crystallisable viral particle containing nucleic acid and protein
ⓓ. a symbiosis between fungal and photosynthetic partners
Correct Answer: a symbiosis between fungal and photosynthetic partners
Explanation: A lichen represents a stable partnership involving a fungal mycobiont and a photosynthetic phycobiont, usually an alga or cyanobacterial partner. The partners belong to recognised biological groups, while the lichen name refers to their integrated association rather than to a separate cellular lineage equivalent to a kingdom. The fungus provides shelter, water, and mineral support, while the photosynthetic partner prepares food. This association-based identity explains why lichens are discussed separately rather than inserted as an additional Whittaker kingdom. The lichen body combines partners from established groups rather than representing a separate cellular lineage.
416. Which feature best explains why viruses, viroids, and prions require separate treatment from the five cellular kingdoms?
ⓐ. They lack normal cellular organisation
ⓑ. They all contain both DNA and RNA
ⓒ. They all perform independent metabolism
ⓓ. They possess tissues without organs
Correct Answer: They lack normal cellular organisation
Explanation: The five kingdoms organise living forms around cellular characters. Viruses contain nucleic acid and protein but no complete cell, viroids are naked infectious RNA, and prions are infectious proteins. Their compositions differ from one another, yet all fall outside ordinary cellular organisation. They do not all contain nucleic acid, and none performs the autonomous metabolism expected of a free-living cell. The shared reason for separate treatment is the absence of a normal cellular body rather than one identical chemical composition. Absence of a normal cell prevents comparison through the same cellular criteria used for Monera through Animalia.
417. The following biological entities are compared.
| Item | Nature |
|---|
| P | Acellular nucleic-acid-protein agent |
| Q | Infectious RNA without protein coat |
| R | Infectious abnormal protein |
| S | algal-fungal symbiotic association (lichen) |
Which set contains items that are not recognised as independent kingdoms in Whittaker's five-kingdom system?
ⓐ. P and Q only
ⓑ. Q and R only
ⓒ. P, Q, R and S
ⓓ. P, R and S only
Correct Answer: P, Q, R and S
Explanation: P represents a virus, Q a viroid, and R a prion. All three are acellular infectious agents and fall outside the ordinary cellular basis of the five kingdoms. S represents a lichen, which is an association between partners rather than an independent kingdom-level organismal group. The four entities are omitted for two related but distinct reasons: lack of cellular organisation in the infectious agents and composite association in the lichen. The table requires both cellularity and organism-versus-association reasoning. P is a virus, Q a viroid, R a prion, and S a lichen association, so every row lies outside ordinary kingdom placement for a different reason.
418. Treating lichens, viruses, viroids, and prions as one additional kingdom would be misleading because:
ⓐ. each member is a multicellular fungus with a chitinous wall
ⓑ. none of the four has a biologically significant association or disease role
ⓒ. all four possess the same nucleic acid enclosed by an identical capsid
ⓓ. it mixes a cellular symbiosis with different acellular agents
Correct Answer: it mixes a cellular symbiosis with different acellular agents
Explanation: Lichens are partnerships between cellular organisms, whereas viruses, viroids, and prions are acellular agents with different compositions. Viruses contain nucleic acid enclosed by protein, viroids are infectious RNA without a protein coat, and prions are infectious proteins. Grouping them together as one kingdom would ignore these fundamental distinctions and the cellular basis of Whittaker's system. Their shared omission from the five kingdoms does not mean that they form a natural, uniform taxonomic group. Shared exclusion from the five kingdoms does not make the four items compositionally or evolutionarily uniform. The proposed category would mix mutualism with agents made of nucleoprotein, naked RNA, or protein alone.
419. A virus is described as non-cellular because it:
ⓐ. lacks a complete cellular organisation
ⓑ. always lacks genetic material
ⓒ. contains tissues but no organs
ⓓ. performs photosynthesis outside a host
Correct Answer: lacks a complete cellular organisation
Explanation: A virus consists essentially of genetic material enclosed by a protein coat and, in some cases, additional coverings. It lacks cytoplasm, ribosomes, and the independent metabolic organisation of a cell. Viruses do contain genetic material, either RNA or DNA, so non-cellular does not mean chemically empty. They also do not form tissues or carry out photosynthesis. Their particle-like organisation explains both their exclusion from cellular kingdoms and their dependence on host cells for replication. It contains biological macromolecules but has no cytoplasm, organelles, or autonomous cellular machinery. Its structure is a particle rather than a self-maintaining prokaryotic or eukaryotic cell.
420. Outside a suitable living cell, many viruses may exist in an inert or crystalline state. This condition shows that extracellular viruses:
ⓐ. carry out rapid independent metabolism
ⓑ. behave more like non-living particles
ⓒ. reproduce by binary fission
ⓓ. develop tissues and organs
Correct Answer: behave more like non-living particles
Explanation: Outside host cells, viruses do not perform autonomous metabolism, growth, or reproduction. Some can be crystallised and remain inert until they encounter a suitable host. This extracellular behaviour resembles non-living matter and forms one side of the living-non-living boundary. The viral particle still retains the organisation needed to initiate infection under appropriate conditions, but it does not function as an independent cell. Binary fission and tissue development require cellular systems that viruses lack. Crystallinity and metabolic inactivity outside a host resemble properties of non-living chemical particles. The same particle can regain biological activity only after entering a compatible living cell.
