Question 71:
Which of the following adaptations helps to prevent water loss during dry conditions?
A) Large leaf area
B) Thick cuticle
C) Open stomata
D) Abundant root hairs
Answer: B) Thick cuticle
Explanation: A thick cuticle minimizes water loss by creating a barrier to evaporation, helping plants retain moisture in dry conditions.
Question 72:
What is the term for the pressure that develops in the phloem due to the accumulation of sugars?
A) Hydrostatic pressure
B) Turgor pressure
C) Osmotic pressure
D) Root pressure
Answer: B) Turgor pressure
Explanation: Turgor pressure develops when sugars accumulate in the phloem, creating pressure that drives the flow of sap through the plant.
Question 73:
Which of the following elements is essential for the formation of chlorophyll in plants?
A) Nitrogen
B) Iron
C) Magnesium
D) Potassium
Answer: C) Magnesium
Explanation: Magnesium is a central component of chlorophyll, which is essential for photosynthesis.
Question 74:
The movement of water through plant tissues can be described as:
A) Unidirectional only
B) Bidirectional only
C) Both unidirectional and bidirectional
D) Random
Answer: A) Unidirectional only
Explanation: The movement of water in xylem is typically unidirectional, flowing from the roots to the leaves.
Question 75:
What physiological process occurs in the roots to maintain water uptake?
A) Photosynthesis
B) Respiration
C) Transpiration
D) Root pressure
Answer: D) Root pressure
Explanation: Root pressure is a physiological process that helps push water upward from the roots, particularly when transpiration rates are low.
Question 76:
Which factor would most likely decrease the rate of transpiration?
A) High temperature
B) High humidity
C) Strong winds
D) Bright sunlight
Answer: B) High humidity
Explanation: High humidity reduces the water vapor gradient between the leaf interior and the atmosphere, thus decreasing the rate of transpiration.
Question 77:
In which structure do guard cells regulate the opening and closing?
A) Stomata
B) Xylem
C) Phloem
D) Leaf epidermis
Answer: A) Stomata
Explanation: Guard cells surround stomata and control their opening and closing to regulate gas exchange and water loss.
Question 78:
The primary role of the endodermis in roots is to:
A) Absorb water
B) Control the movement of water and minerals into the vascular system
C) Store nutrients
D) Conduct photosynthesis
Answer: B) Control the movement of water and minerals into the vascular system
Explanation: The endodermis acts as a selective barrier, regulating what enters the vascular tissue from the soil.
Question 79:
Which type of plant root is specialized for climbing and support?
A) Taproot
B) Adventitious root
C) Fibrous root
D) Aerial root
Answer: D) Aerial root
Explanation: Aerial roots are specialized roots that grow above ground and can provide support and help the plant climb.
Question 80:
Which of the following processes allows for the passive movement of water across cell membranes?
A) Active transport
B) Facilitated diffusion
C) Osmosis
D) Bulk flow
Answer: C) Osmosis
Explanation: Osmosis is the passive movement of water across a semipermeable membrane from an area of low solute concentration to high solute concentration.
Leave a comment