Q1. Which of the following structures in plants is primarily responsible for gas exchange?
a) Stomata
b) Xylem
c) Phloem
d) Root hairs
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Correct Answer: a) Stomata
Explanation: Stomata are tiny pores present on the surface of leaves and stems of plants. They regulate gas exchange, allowing carbon dioxide to enter for photosynthesis and oxygen to exit during respiration. Stomata also control water loss through transpiration.
Q2. What is the primary waste product of photosynthesis in plants?
a) Oxygen
b) Carbon dioxide
c) Glucose
d) Water
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Correct Answer: a) Oxygen
Explanation: During photosynthesis, plants use carbon dioxide and water to produce glucose and oxygen. While glucose is a product utilized by the plant for energy, oxygen is released as a byproduct into the atmosphere, facilitating aerobic respiration in plants and animals.
Q3. In which part of the plant does most of the water absorption occur?
a) Stem
b) Leaves
c) Roots
d) Flowers
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Correct Answer: c) Roots
Explanation: Roots are the primary organs responsible for water absorption in plants. They have specialized structures such as root hairs and root cells with osmotic capabilities that allow them to absorb water and minerals from the soil.
Q4. Which of the following is NOT a method of water loss in plants?
a) Transpiration
b) Evaporation
c) Osmosis
d) Guttation
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Correct Answer: c) Osmosis
Explanation: Osmosis is a process by which water moves across a semipermeable membrane from an area of low solute concentration to an area of high solute concentration. It is not a method of water loss but rather a mechanism of water uptake by plant cells.
Q5. What is the term for the process by which plants release water vapor into the atmosphere through small pores on their leaves?
a) Transpiration
b) Respiration
c) Photosynthesis
d) Evaporation
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Correct Answer: a) Transpiration
Explanation: Transpiration is the process by which plants release water vapor into the atmosphere through small openings called stomata on their leaves. It plays a crucial role in maintaining plant hydration, nutrient uptake, and temperature regulation.
Q6. Which of the following structures in plants is responsible for the transport of water and minerals from roots to leaves?
a) Xylem
b) Phloem
c) Stomata
d) Guard cells
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Correct Answer: a) Xylem
Explanation: Xylem is a vascular tissue in plants responsible for transporting water and minerals from the roots to the leaves. It consists of hollow tubes made of specialized cells called tracheids and vessel elements, providing structural support and facilitating upward movement of water through capillary action.
Q7. What is the primary function of the stomata in plants?
a) Gas exchange
b) Water absorption
c) Photosynthesis
d) Nutrient transport
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Correct Answer: a) Gas exchange
Explanation: Stomata are small pores found on the surfaces of leaves and stems in plants. Their primary function is to regulate gas exchange, allowing for the uptake of carbon dioxide needed for photosynthesis and the release of oxygen and water vapor produced during photosynthesis and respiration.
Q8. Which of the following is NOT a role of roots in plants?
a) Water absorption
b) Nutrient storage
c) Photosynthesis
d) Anchoring the plant
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Correct Answer: c) Photosynthesis
Explanation: Roots in plants primarily function in water absorption from the soil, anchoring the plant in the ground, and storing nutrients. Photosynthesis primarily occurs in the leaves, where chlorophyll captures sunlight energy to produce glucose from carbon dioxide and water.
Q9. Which of the following is a waste product of cellular respiration in plants?
a) Oxygen
b) Carbon dioxide
c) Glucose
d) Water
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Correct Answer: b) Carbon dioxide
Explanation: Cellular respiration in plants, as in animals, involves the breakdown of glucose in the presence of oxygen to produce energy, carbon dioxide, and water. Carbon dioxide is a waste product released by plant cells during cellular respiration and is expelled through stomata.
Q10. What is the term for the process by which excess water and waste products are removed from plant cells?
a) Transpiration
b) Excretion
c) Respiration
d) Osmosis
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Correct Answer: b) Excretion
Explanation: Excretion in plants involves the removal of excess water, metabolic wastes, and toxic substances from plant cells. This process occurs through various mechanisms, including the secretion of waste products into vacuoles or their storage in specialized structures such as trichomes.