Which of the following leaf modifications occur(s) in the desert areas to inhibit water loss ? 1. Hard and waxy leaves 2. Tiny leaves 3. Thorns instead of leaves Select the correct answer using the code given below :
- (a) 2 and 3 only
- (b) 2 only
- (c) 3 only
- (d) 1, 2 and 3 ✓ UPSC's answer
Why the answer is (d)
• Desert plants (xerophytes) minimise transpiration through leaf adaptations.
• Hard, waxy (cuticle-thickened) leaves (1) seal in moisture; tiny leaves (2) reduce the surface area exposed to sun and wind; in cacti and euphorbias, leaves are reduced to thorns (3) and the green stem takes over photosynthesis.
• All three modifications inhibit water loss.
• Hence 1, 2 and 3, option (d).
Why the other options are wrong
- (a) 2 and 3 only
- Waxy leaves also reduce water loss.
- (b) 2 only
- Waxy leaves and thorns also help.
- (c) 3 only
- Tiny and waxy leaves also help.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2018, held on 3 June 2018. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.