Q11. What process in plants involves the loss of water vapor through leaves?
a) Photosynthesis
b) Transpiration
c) Respiration
d) Condensation
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Correct Answer: b) Transpiration
Explanation: Transpiration is the process in plants that involves the loss of water vapor through the leaves. It occurs mainly through the stomata, which are small openings on the leaf surface. Transpiration helps in the movement of water and nutrients from the roots to different parts of the plant and also aids in temperature regulation.
Q12. What are the small green structures in plant cells where photosynthesis occurs?
a) Mitochondria
b) Chloroplasts
c) Vacuoles
d) Nuclei
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Correct Answer: b) Chloroplasts
Explanation: Chloroplasts are the small green structures in plant cells where photosynthesis takes place. They contain the pigment chlorophyll, which absorbs sunlight needed for the process. Chloroplasts convert light energy into chemical energy, producing oxygen and glucose from carbon dioxide and water.
Q13. Which element is a primary component of chlorophyll in plants?
a) Iron
b) Magnesium
c) Calcium
d) Potassium
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Correct Answer: b) Magnesium
Explanation: Magnesium is a primary component of chlorophyll in plants. This element is central to the chlorophyll molecule and plays a vital role in capturing light energy during photosynthesis. Magnesium deficiency in plants can lead to chlorosis, a condition where leaves turn yellow due to insufficient chlorophyll.
Q14. What term describes plants that grow on other plants but do not derive nutrients from them?
a) Parasitic
b) Saprophytic
c) Epiphytic
d) Symbiotic
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Correct Answer: c) Epiphytic
Explanation: Epiphytic plants grow on other plants but do not derive nutrients from their hosts. They are not parasitic; instead, they use the host merely for physical support. Epiphytes absorb nutrients and water from the air, rain, and sometimes from debris accumulating around them. Common examples include certain orchids and ferns.
Q15. Which of the following is not a primary macronutrient for plant growth?
a) Nitrogen
b) Phosphorus
c) Potassium
d) Silicon
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Correct Answer: d) Silicon
Explanation: Silicon is not considered a primary macronutrient for plant growth. The primary macronutrients are nitrogen (N), phosphorus (P), and potassium (K). These elements are crucial for plant growth and development, playing key roles in processes such as photosynthesis, nutrient transport, and water regulation.
Q16. In plants, what is the main purpose of nectar?
a) Attracting pollinators
b) Providing nutrients to leaves
c) Protecting from herbivores
d) Storing excess water
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Correct Answer: a) Attracting pollinators
Explanation: The main purpose of nectar in plants is to attract pollinators like bees, butterflies, and hummingbirds. Nectar is a sweet liquid produced by glands called nectaries, usually found in flowers. The presence of nectar encourages pollinators to visit the flower, aiding in the plant’s reproductive process through pollination.
Q17. Which hormone in plants regulates growth and responses to light and gravity?
a) Ethylene
b) Auxin
c) Cytokinin
d) Gibberellin
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Correct Answer: b) Auxin
Explanation: Auxin is a plant hormone that plays a key role in regulating growth and responses to environmental stimuli like light and gravity. It promotes cell elongation, influences the direction of growth by regulating differential growth, and is involved in various developmental processes, including fruit development and root formation.
Q18. Which process describes the movement of water and nutrients from roots to leaves in plants?
a) Osmosis
b) Diffusion
c) Transpiration pull
d) Capillary action
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Correct Answer: c) Transpiration pull
Explanation: Transpiration pull is the process that describes the movement of water and nutrients from roots to leaves in plants. It is driven by the evaporation of water from the leaf surfaces, creating a negative pressure that pulls water upwards from the roots through the xylem vessels. This process is essential for the transport of water and dissolved nutrients.
Q19. What is the primary function of roots in most plants?
a) Photosynthesis
b) Support and anchorage
c) Seed dispersion
d) Producing flowers
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Correct Answer: b) Support and anchorage
Explanation: The primary function of roots in most plants is to provide support and anchorage. They anchor the plant firmly into the ground and also play a critical role in water and nutrient absorption from the soil. Roots can also store food and nutrients and are vital for the overall stability and growth of the plant.
Q20. Carnivorous plants like the Venus Flytrap obtain nutrients mainly from:
a) Photosynthesis
b) Absorbing minerals from the soil
c) Capturing and digesting insects
d) Filtering nutrients from water
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Correct Answer: c) Capturing and digesting insects
Explanation: Carnivorous plants like the Venus Flytrap obtain nutrients primarily by capturing and digesting insects. They have evolved specialized structures to trap insects, which they then digest to supplement their nutrient intake, especially nitrogen and phosphorus, which are often scarce in their native environments. Despite their carnivorous behavior, these plants still perform photosynthesis like other plants.