1. In plants, growth is best defined as:
ⓐ. A temporary increase in water content and cell volume
ⓑ. An irreversible increase in size usually accompanied by dry mass increase
ⓒ. A seasonal change in colour and leaf arrangement
ⓓ. A reversible change in shape caused by external conditions
Correct Answer: An irreversible increase in size usually accompanied by dry mass increase
Explanation: Plant growth refers to a permanent and irreversible increase in size, volume, mass, or number of cells. It is not just a short-term swelling caused by water entry, because that may be reversible. True growth usually involves synthesis of new protoplasm and structural materials, which adds to dry matter. This makes the plant body larger in a lasting way. In biology, the word irreversible is important because it separates real growth from temporary physical changes. Therefore, plant growth is understood as a permanent increase linked with living activity.
2. Which feature most clearly distinguishes growth in living plants from enlargement in many non-living objects?
ⓐ. It occurs by internal cell division and cell enlargement
ⓑ. It always happens at the same rate in all regions
ⓒ. It depends only on the absorption of external materials
ⓓ. It stops completely after the seedling stage
Correct Answer: It occurs by internal cell division and cell enlargement
Explanation: Growth in living plants is produced from within the organism through active biological processes. Cells divide, enlarge, and contribute to the formation of tissues and organs. In contrast, many non-living things may appear to grow only by external deposition of material on their surface. This internal nature of growth is a key sign of life. It shows that growth in plants is organized and controlled by metabolism. Because of this, internal cell division and enlargement are central to the concept of living growth.
3. In higher plants, growth is described as indeterminate mainly because:
ⓐ. Plants grow only during the reproductive phase
ⓑ. Plants continue to produce new organs throughout life
ⓒ. Plants always increase in height at a fixed speed
ⓓ. Plants show growth only in underground parts
Correct Answer: Plants continue to produce new organs throughout life
Explanation: Indeterminate growth means that plants retain the ability to grow for a long period, often throughout their life. This happens because meristematic tissues remain active and keep producing new cells. As a result, plants can continuously form leaves, branches, roots, flowers, and other structures. The plant body is therefore not fixed at an early stage in the way many animals are. This continuing capacity for organ formation is a major reason why plant growth is called indeterminate. It reflects the persistent developmental potential of meristems.
4. Which structure is primarily responsible for the indeterminate growth of plants?
ⓐ. Permanent tissues in mature stems
ⓑ. Sclerenchyma cells in supporting regions
ⓒ. Meristematic tissues at growing regions
ⓓ. Dead xylem elements in vascular bundles
Correct Answer: Meristematic tissues at growing regions
Explanation: Meristematic tissues contain actively dividing cells that remain capable of producing new cells repeatedly. These tissues occur at specific growing regions such as the root apex, shoot apex, and in some cases lateral meristems. Because they do not lose their dividing capacity early, plants can continue growing and adding new organs. This is the biological basis of indeterminate growth. Mature permanent tissues mainly perform specialized functions and usually do not divide actively. Therefore, meristems are the main centres that maintain continuous plant growth.
5. The term open form of growth in plants means that:
ⓐ. The final body design is not fixed early and new organs can be added later
ⓑ. Plant cells remain exposed directly to the atmosphere throughout life
ⓒ. Every plant develops only a simple and unbranched body plan
ⓓ. Growth occurs only in organs that are externally visible
Correct Answer: The final body design is not fixed early and new organs can be added later
Explanation: Plants are said to have an open form of growth because their body plan is not fully closed or completed at an early developmental stage. New organs such as leaves, branches, flowers, and roots can continue to arise as growth proceeds. This makes the plant body flexible and expandable over time. The presence of active meristems allows repeated addition of structures according to internal and external conditions. As a result, the final appearance of a plant may keep changing during its life. This continuing organ formation is the essence of open growth form.
6. Which statement correctly relates indeterminate growth and open form of growth in plants?
ⓐ. Both mean that all plant cells divide equally throughout life
ⓑ. Both arise because plants can keep producing new cells and organs from meristems
ⓒ. Both indicate that plants do not undergo any maturation
ⓓ. Both are seen only in aquatic flowering plants
Correct Answer: Both arise because plants can keep producing new cells and organs from meristems
Explanation: Indeterminate growth and open form of growth are closely connected ideas in plant biology. Indeterminate growth refers to the continuing capacity for growth, while open form describes the continuing addition of organs and body parts. Both are possible because meristematic tissues remain active and keep supplying new cells. These cells later differentiate and contribute to new structures. The plant body is therefore dynamic rather than fixed. So, the common biological basis of both features is the persistent activity of meristems.
7. Which of the following is a characteristic feature of plant growth?
ⓐ. It is always reversible under normal conditions
ⓑ. It is limited to a single phase of life
ⓒ. It commonly involves an increase in cell number or cell size
ⓓ. It occurs without any metabolic activity
Correct Answer: It commonly involves an increase in cell number or cell size
Explanation: Plant growth is brought about mainly by an increase in the number of cells, the size of cells, or both. These changes occur through active metabolism, synthesis of cellular material, and regulated developmental processes. Growth is not simply a passive event and it is not normally reversible. In many cases, once tissues have truly grown, they do not return to their earlier state. The increase may be seen in length, girth, mass, or organ development. Therefore, increase in cell number or size is a central characteristic of plant growth.
8. A newly formed leaf, root, or flower appearing later in the life of a plant mainly demonstrates:
ⓐ. Closed body organization
ⓑ. Indeterminate and open growth habit
ⓒ. Absence of meristematic control
ⓓ. Reversible growth response
Correct Answer: Indeterminate and open growth habit
Explanation: When a plant continues to form new organs later in life, it shows that its development is not completed at an early stage. This reflects both indeterminate growth and open body form. The plant retains active meristems that keep generating cells, and these cells organize into fresh structures. Such repeated organ production is one of the clearest differences between plants and many animals. It also explains why plant shape can keep changing with age and environment. Thus, the late appearance of new organs is strong evidence of open and indeterminate growth.
9. Why are plants often able to keep increasing in length at root and shoot tips?
ⓐ. Because mature xylem cells repeatedly regain division ability
ⓑ. Because cork cells at the surface become permanently meristematic
ⓒ. Because apical meristems remain active in these growing regions
ⓓ. Because all epidermal cells divide continuously in equal proportion
Correct Answer: Because apical meristems remain active in these growing regions
Explanation: Root and shoot tips contain apical meristems, which are groups of actively dividing cells. These cells continuously produce new daughter cells that later enlarge and differentiate into various tissues. This activity allows elongation of the root and shoot over time. Since these meristems remain functional for long periods, the plant can continue primary growth. Mature tissues generally do not contribute much to this process. Therefore, the persistent activity of apical meristems explains continued increase in length at the tips.
10. Which statement about the endpoint of plant growth is most accurate?
ⓐ. Plant growth always ends immediately after seed germination
ⓑ. Plant growth ends only when the first leaves are fully expanded
ⓒ. Plant growth may continue for life because some meristems remain active
ⓓ. Plant growth stops once vascular tissues are formed
Correct Answer: Plant growth may continue for life because some meristems remain active
Explanation: In many plants, growth does not have a sharply fixed endpoint because meristematic tissues continue functioning. As long as these meristems remain active and conditions are suitable, new cells and organs can keep being produced. This is why plant growth is often called indeterminate. It does not mean that every tissue grows forever, but that the organism as a whole retains ongoing growth potential. Some parts mature and stop expanding, while other regions continue developing. Thus, lifelong growth potential is linked to the persistence of active meristems.
11. Which option best explains why plant growth is called a living process?
ⓐ. It depends on organized metabolic and cellular activity
ⓑ. It occurs without using energy from the organism
ⓒ. It takes place only in dead supportive tissues
ⓓ. It is caused only by surface deposition of materials
Correct Answer: It depends on organized metabolic and cellular activity
Explanation: Growth in plants is a living process because it requires active metabolism, synthesis of new substances, and controlled cellular events. Cell division, enlargement, and formation of new tissues do not happen passively. They depend on energy, enzymes, genetic control, and coordinated physiological activity. This separates plant growth from simple external enlargement seen in non-living materials. The increase in size is therefore a result of life processes operating within cells. Because of this close link with metabolism and organization, growth is fundamentally a living phenomenon.
12. Which of the following would be the best example of open growth form in a plant?
ⓐ. A mature leaf maintaining the same shape for a few days
ⓑ. A seed remaining dormant without visible structural change
ⓒ. A tree producing new branches and leaves year after year
ⓓ. A dry fruit losing water after harvest
Correct Answer: A tree producing new branches and leaves year after year
Explanation: Open growth form means that the plant body can continue adding new parts over time instead of remaining permanently fixed. A tree that keeps producing fresh branches and leaves each year shows this feature clearly. Its apical and lateral meristems continue to generate new cells, which later form new organs. This ability gives plants a flexible body organization that changes with age and conditions. The plant is therefore not developmentally closed at an early stage. Repeated yearly production of new structures is a classic example of open form of growth.
13. A wilted herb becomes firm and slightly larger a few hours after watering, but its dry mass remains unchanged. This change is best described as:
ⓐ. Permanent growth caused by formation of new tissues
ⓑ. Secondary growth produced by active cambium
ⓒ. Development of a new organ from the shoot tip
ⓓ. Temporary enlargement caused mainly by water uptake
Correct Answer: Temporary enlargement caused mainly by water uptake
Explanation: True growth in plants is permanent and usually linked with synthesis of new cellular material. In this case, the plant becomes larger only because cells regain water and turgidity. Since the dry mass does not increase, no clear evidence of new protoplasm or tissue formation is present. Such enlargement is reversible if the plant loses water again. Therefore, the change is a temporary physical expansion rather than actual growth.
14. A leaf of a young plant reaches a fixed final size, yet the plant continues producing new leaves and branches. Which interpretation is correct?
ⓐ. The whole plant has shifted from indeterminate to reversible growth
ⓑ. A plant may be indeterminate overall even when individual organs become determinate
ⓒ. Indeterminate growth means every organ keeps enlarging throughout life
ⓓ. Open growth is absent once the first leaf becomes mature
Correct Answer: A plant may be indeterminate overall even when individual organs become determinate
Explanation: Indeterminate growth refers mainly to the plant as a whole, not to every single organ. Many plant organs such as leaves, flowers, and fruits eventually attain a definite size and stop enlarging. Even so, the plant can keep growing because meristems continue producing new cells and new organs. This is why a plant may remain developmentally open despite determinate growth in some parts. The example does not contradict indeterminate growth at the organism level.
15. Which of the following is the best non-example of plant growth?
ⓐ. Opening of stomata during the daytime
ⓑ. Elongation of a young internode
ⓒ. Formation of lateral roots in a seedling
ⓓ. Increase in stem girth by cambial activity
Correct Answer: Opening of stomata during the daytime
Explanation: Opening of stomata is a physiological movement caused mainly by changes in guard cell turgor. It does not involve permanent increase in size, dry mass, or formation of new tissue. In contrast, internode elongation, lateral root formation, and cambial thickening are all true growth processes. These involve cell division, enlargement, or addition of new tissues. So stomatal opening is a useful non-example that helps distinguish movement from growth.
16. A salt crystal and a growing root tip both increase in size. What is the most important difference between them?
ⓐ. Both enlarge only by adding material on the outer surface
ⓑ. Both depend on internal cell division and tissue formation
ⓒ. Root growth is internal and organized, whereas crystal growth occurs by external addition
ⓓ. Crystal growth is reversible, whereas root growth is always reversible
Correct Answer: Root growth is internal and organized, whereas crystal growth occurs by external addition
Explanation: A root tip grows through living processes such as cell division, cell enlargement, and tissue differentiation. This growth is internally controlled and organized by meristematic activity. A salt crystal, however, becomes larger mainly by deposition of material from outside onto its surface. It does not involve cells, metabolism, or developmental control. This contrast clearly separates biological growth from simple increase in size in non-living matter.
17. Assertion (A): Open form of growth means all mature tissues of a plant continue dividing throughout life. Reason (R): New organs may continue to arise because meristematic regions remain active.
ⓐ. Both A and R are true, and R is the correct explanation of A
ⓑ. Both A and R are true, but R is not the correct explanation of A
ⓒ. A is true, but R is false
ⓓ. A is false, but R is true
Correct Answer: A is false, but R is true
Explanation: Open form of growth does not mean that all mature tissues keep dividing. Most mature permanent tissues lose active dividing capacity and perform specialized functions. The plant shows open growth because meristematic regions remain active and continue producing new cells and organs. This allows the plant body to keep changing with time. Therefore, the assertion is incorrect, while the reason is correct.
18. Which statement about the location of growth in plants is correct?
ⓐ. Growth is usually localized in meristematic regions rather than occurring equally in all cells
ⓑ. Every mature permanent cell divides continuously throughout the life of the plant
ⓒ. All parts of a plant grow at the same rate under the same conditions
ⓓ. Growth is equally active in the root cap, bark, leaf blade, and xylem vessel
Correct Answer: Growth is usually localized in meristematic regions rather than occurring equally in all cells
Explanation: Plant growth is not distributed uniformly across the entire body. It is mainly localized in regions where meristematic cells are present, such as root and shoot apices and certain lateral meristems. Mature permanent tissues usually do not divide actively like meristems. This is why some regions elongate or thicken while others remain structurally stable. Understanding this localization helps explain why plant growth is controlled and region-specific.
19. A student places equal ink marks at short intervals on a young root. After two days, the distances between marks increase most strongly near the tip, while upper marks change very little. What does this show?
ⓐ. All regions of the root are growing equally, but water loss is uneven
ⓑ. Growth is localized near the growing region close to the root tip
ⓒ. Root growth occurs mainly in the mature region far from the tip
ⓓ. The ink marks prevent cell division only in the upper region
Correct Answer: Growth is localized near the growing region close to the root tip
Explanation: This classic observation shows that growth is not uniform throughout the root. The greatest increase in distance between marks occurs near the active growing region, where cells divide and enlarge. Marks placed farther away show little change because those cells are already mature. The experiment demonstrates localized growth rather than equal expansion in all regions. It also supports the idea that meristematic and nearby elongating regions are the main sites of primary growth.
20. A detached stem segment contains only fully mature tissues and no meristematic region. Which outcome is most likely?
ⓐ. It will continue unlimited primary growth because all living cells can divide
ⓑ. It will show open growth by forming organs from every permanent tissue
ⓒ. It will increase in length rapidly because mature cells elongate indefinitely
ⓓ. It may remain alive for some time, but it is not a major site of new primary growth on its own
Correct Answer: It may remain alive for some time, but it is not a major site of new primary growth on its own
Explanation: Primary growth depends mainly on the activity of meristematic tissues, especially apical meristems. If a detached stem segment lacks such regions, it does not serve as an important site for continued organized elongation. Some mature tissues may remain alive and metabolically active for a while, but that is different from being a true growth centre. Without meristematic activity, new primary growth is greatly limited. This highlights the importance of growth being localized in specialized tissues.
