Desert plants have evolved to survive in places where very little water is available. Which process is reduced to enable them to retain as much water as possible?
A) transpiration
B) translocation
C) respiration
D) digestion
▶️ Answer/Explanation
Ans: A
Transpiration (A) is the process by which plants lose water vapor through their stomata. Desert plants reduce this process to conserve water, often through adaptations like smaller leaves, thick cuticles, or stomata that open at night.
Translocation (B) transports nutrients, respiration (C) releases energy, and digestion (D) occurs in animals, not plants. Since water retention is directly linked to minimizing transpiration, the correct answer is A (Transpiration).
A student set up the experiment shown in the diagram on a hot and dry day. The air bubble moved towards the leafy shoot by 30 mm in 1 hour.
The student was asked to predict and explain the result that would have been obtained on a hot and humid day.
Which row is correct?
▶️ Answer/Explanation
Ans: B
On a hot and humid day, the rate of transpiration decreases because the air already contains high water vapor, reducing the water potential gradient between the leaf and the atmosphere. This results in a smaller movement of the air bubble compared to a hot and dry day.
Option B correctly states that the bubble would move less than 30 mm due to lower transpiration rate caused by reduced evaporation in humid conditions. The other options either incorrectly predict the bubble movement or misattribute the cause.