Question 31:
Which of the following is NOT a function of the xylem?
A) Transport of water
B) Transport of nutrients
C) Structural support
D) Storage of carbohydrates
Answer: D) Storage of carbohydrates
Explanation: Xylem primarily transports water and minerals and provides structural support but does not store carbohydrates; this is the function of phloem and parenchyma cells.
Question 32:
What is the function of the pericycle in plant roots?
A) Nutrient absorption
B) Water storage
C) Formation of lateral roots
D) Photosynthesis
Answer: C) Formation of lateral roots
Explanation: The pericycle is a layer of cells in the root that can give rise to lateral roots, helping the plant to explore a larger volume of soil for water and nutrients.
Question 33:
The primary component of the plant cell wall that provides strength is:
A) Cellulose
B) Lignin
C) Hemicellulose
D) Pectin
Answer: A) Cellulose
Explanation: Cellulose is a polysaccharide that forms the primary structural component of the plant cell wall, providing rigidity and strength.
Question 34:
Which process allows plants to take in minerals from the soil?
A) Diffusion
B) Filtration
C) Osmosis
D) Active transport
Answer: D) Active transport
Explanation: Active transport is required for the uptake of minerals against their concentration gradient, allowing plants to absorb essential nutrients from the soil.
Question 35:
Which plant hormone is primarily involved in regulating stomatal closure during water stress?
A) Auxin
B) Cytokinins
C) Abscisic acid (ABA)
D) Ethylene
Answer: C) Abscisic acid (ABA)
Explanation: Abscisic acid (ABA) signals stomatal closure during water stress, helping to conserve water in the plant.
Question 36:
In plants, the term “hydraulic conductivity” refers to:
A) The ability of water to move through soil
B) The rate at which water moves through plant tissues
C) The capacity of roots to absorb water
D) The resistance of xylem to water flow
Answer: B) The rate at which water moves through plant tissues
Explanation: Hydraulic conductivity measures how easily water can move through plant tissues, particularly in xylem.
Question 37:
What is the primary source of energy for the active transport of nutrients in plants?
A) Sunlight
B) ATP
C) Glucose
D) Photosynthesis
Answer: B) ATP
Explanation: Active transport in plants requires energy, which is provided by ATP (adenosine triphosphate) produced during cellular respiration.
Question 38:
The term “sink” in the context of phloem transport refers to:
A) A source of water
B) An area of nutrient production
C) A site where nutrients are consumed or stored
D) An area of photosynthesis
Answer: C) A site where nutrients are consumed or stored
Explanation: In phloem transport, a “sink” is any part of the plant that consumes or stores sugars, such as roots, fruits, and developing leaves.
Question 39:
Which of the following adaptations helps reduce water loss in plants?
A) Large leaves
B) Thick cuticle
C) Open stomata
D) Shallow roots
Answer: B) Thick cuticle
Explanation: A thick cuticle on leaf surfaces minimizes water loss by reducing evaporation, helping the plant retain moisture.
Question 40:
The main tissue responsible for the transport of food in plants is:
A) Xylem
B) Sclerenchyma
C) Phloem
D) Parenchyma
Answer: C) Phloem
Explanation: Phloem is the vascular tissue responsible for the transport of organic nutrients, particularly sugars, throughout the plant.
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