Q21. The process of converting atmospheric nitrogen into a usable form for plants is called:
a) Nitrification
b) Ammonification
c) Denitrification
d) Nitrogen fixation
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Correct Answer: d) Nitrogen fixation
Explanation: Nitrogen fixation is carried out by nitrogen-fixing bacteria, which convert atmospheric nitrogen into ammonia or other nitrogen compounds.
Q22. Which of the following is not a type of symbiotic relationship between plants and other organisms?
a) Mutualism
b) Commensalism
c) Parasitism
d) Predation
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Correct Answer: d) Predation
Explanation: Predation involves one organism consuming another organism for food and is not a symbiotic relationship.
Q23. The process by which green plants utilize light energy to synthesize organic compounds is called:
a) Respiration
b) Photosynthesis
c) Fermentation
d) Oxidation
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Correct Answer: b) Photosynthesis
Explanation: Photosynthesis is the process by which green plants use light energy to convert carbon dioxide and water into glucose and oxygen.
Q24. Which of the following is a carnivorous plant?
a) Venus flytrap
b) Fern
c) Cactus
d) Orchid
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Correct Answer: a) Venus flytrap
Explanation: Venus flytrap is a carnivorous plant that captures and digests insects for nutrients.
Q25. The transfer of pollen from the anther to the stigma of the same flower or another flower of the same plant is called:
a) Self-pollination
b) Cross-pollination
c) Wind pollination
d) Animal pollination
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Correct Answer: a) Self-pollination
Explanation: Self-pollination occurs when pollen is transferred from the anther to the stigma of the same flower or another flower on the same plant.
Q26. Which of the following plant hormones is responsible for the ripening of fruits?
a) Gibberellin
b) Ethylene
c) Abscisic acid
d) Cytokinin
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Correct Answer: b) Ethylene
Explanation: Ethylene is a plant hormone that promotes fruit ripening and senescence.
Q27. The process by which plants respond to stimuli such as light, gravity, and touch is called:
a) Transpiration
b) Photosynthesis
c) Tropism
d) Dormancy
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Correct Answer: c) Tropism
Explanation: Tropism is the growth or movement of a plant in response to an external stimulus, such as light (phototropism) or gravity (gravitropism).
Q28. Which of the following is a method of vegetative propagation in plants?
a) Budding
b) Fertilization
c) Germination
d) Pollination
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Correct Answer: a) Budding
Explanation: Budding involves the formation of a new individual from a bud or outgrowth on the parent plant.
Q29. The innermost layer of the stem responsible for producing new cells is called the:
a) Epidermis
b) Cortex
c) Cambium
d) Xylem
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Correct Answer: c) Cambium
Explanation: The cambium is a layer of meristematic tissue in the stem that produces new cells for secondary growth.
Q30. Which of the following plant tissues is responsible for providing mechanical support?
a) Xylem
b) Phloem
c) Parenchyma
d) Sclerenchyma
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Correct Answer: d) Sclerenchyma
Explanation: Sclerenchyma cells have thick, lignified cell walls that provide mechanical support to plant tissues.