Q2 · UPSC Prelims 2018 · Set A · Environment and Ecology

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Which of the following leaf modifications occur(s) in the desert areas to inhibit water loss?1.Hard and waxy leaves2.Tiny leaves3.Thorns instead of leavesSelect the correct answer using the code given below:

A 2 and 3 only
B 2 only
C 3 only
D 1, 2 and 3

Correct answer: (d) 1, 2 and 3

Explanation

  1. A

    2 and 3 only

    (a) 2 and 3 only. Tiny leaves and thorns do cut transpiration in deserts, but they are not the full set. Hard, waxy cuticles also inhibit water loss, so dropping statement 1 leaves the code incomplete and not the key.

  2. B

    2 only

    (b) 2 only. Tiny leaves reduce surface area, yet xerophytes also use waxy surfaces and thorns. Isolating one adaptation understates desert morphology, so this letter is not the key.

  3. C

    3 only

    (c) 3 only. Thorns replacing leaves (as in many cacti) are one xerophytic device, not the only one listed. Hard waxy leaves and reduced leaf size also inhibit water loss, so 3-only is not the key.

  4. D

    1, 2 and 3

    (d) 1, 2 and 3. (d) Official key: Desert plants reduce transpiration with a thick waxy cuticle, tiny or rolled leaves, and thorns instead of leaves. All three modifications in the stem inhibit water loss, so the all-correct code is the stored key.

Summary. Official key is (d) 1, 2 and 3. Xerophytes limit evaporation with hard waxy leaves, reduced leaf area, and thorns in place of leaves. Each listed modification is a genuine desert adaptation. Codes that omit any one of them are incomplete. Honour the stored letter (d).

Same topic · past papers

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  1. 2026 · Q39 · General Studies · 2 marks

    Which of the following statements with reference to Lake Turkana is/are correct? 1. It is the largest desert lake in the world. 2. The lake is situated in South Sudan along the eastern fringe of the Sahara desert. 3. The lake is listed as a UNESCO World Heritage Site and is also referred to as the 'Jade Sea'. Select the answer using the code given below:

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