Question 41:
The process by which water moves from the soil into plant roots is called:
A) Transpiration
B) Absorption
C) Evaporation
D) Filtration
Answer: B) Absorption
Explanation: Absorption refers to the process by which water and minerals move from the soil into plant roots through root hairs and other structures.
Question 42:
What is the primary driving force behind the movement of water in the xylem during the day?
A) Root pressure
B) Capillary action
C) Transpiration pull
D) Osmosis
Answer: C) Transpiration pull
Explanation: During the day, transpiration pull creates a negative pressure that helps draw water up from the roots through the xylem.
Question 43:
Which type of transport is mainly responsible for the movement of sucrose in phloem?
A) Passive transport
B) Facilitated diffusion
C) Active transport
D) Simple diffusion
Answer: C) Active transport
Explanation: The movement of sucrose into phloem is often an active process, requiring energy to transport sugars against their concentration gradient.
Question 44:
The root cap is primarily involved in:
A) Nutrient absorption
B) Protecting the root meristem
C) Water transport
D) Photosynthesis
Answer: B) Protecting the root meristem
Explanation: The root cap protects the delicate meristematic tissue at the root tip as it pushes through the soil.
Question 45:
Which of the following factors does NOT affect the rate of transpiration?
A) Temperature
B) Humidity
C) Soil pH
D) Wind speed
Answer: C) Soil pH
Explanation: While temperature, humidity, and wind speed significantly affect the rate of transpiration, soil pH has a more indirect effect on overall plant health rather than directly influencing transpiration rates.
Question 46:
What is the function of aerenchyma in aquatic plants?
A) Nutrient storage
B) Gas exchange and buoyancy
C) Water retention
D) Photosynthesis
Answer: B) Gas exchange and buoyancy
Explanation: Aerenchyma consists of loosely packed cells with large air spaces that facilitate gas exchange and help keep aquatic plants buoyant.
Question 47:
Which part of the plant is responsible for the majority of nutrient storage?
A) Leaves
B) Roots
C) Stems
D) Flowers
Answer: B) Roots
Explanation: Roots serve as storage organs for carbohydrates and other nutrients, allowing the plant to draw on these reserves during periods of growth or stress.
Question 48:
The majority of water absorbed by roots comes from which part of the soil?
A) Topsoil
B) Subsoil
C) Bedrock
D) All soil layers equally
Answer: A) Topsoil
Explanation: The topsoil layer typically contains the highest concentration of nutrients and moisture, making it the primary source of water for roots.
Question 49:
The transport of nutrients in the phloem is mainly through:
A) Vascular bundles
B) Sieve tubes
C) Tracheids
D) Xylem vessels
Answer: B) Sieve tubes
Explanation: Sieve tubes are specialized structures in phloem that facilitate the transport of nutrients and sugars throughout the plant.
Question 50:
Which of the following structures helps in increasing the surface area for absorption in roots?
A) Stomata
B) Root hairs
C) Xylem vessels
D) Guard cells
Answer: B) Root hairs
Explanation: Root hairs are extensions of root epidermal cells that increase the surface area for water and nutrient absorption from the soil.
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