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Q2. In nature, which of the following is/are most likely to be found surviving on a surface without soil? 1. Fern 2. Lichen 3. Moss 4. Mushroom Select the correct answer using the code given below:

In nature, which of the following is/are most likely to be found surviving on a surface without soil?

  1. Fern
  2. Lichen
  3. Moss
  4. Mushroom

Select the correct answer using the code given below:

Select the correct option below (or cross out options to eliminate)

Official Answer Key & Detailed Solution

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Click any option above to test yourself under exam conditions, or reveal the explanation directly.

Official UPSC Answer KeyUPSC Prelims 2021 • Environment and Ecology

Correct Answer: Option (C) — 2 and 3

Concept & Option Breakdown

Standard Reference Verified
  • Lichens are pioneer organisms capable of growing on bare rocks, tree bark, and non-soil substrates as they derive nutrients from air and moisture.
  • Mosses are non-vascular plants that lack true roots and absorb water and nutrients directly across their surfaces, attaching to bare rocks and walls via rhizoids.
  • Ferns are vascular plants that typically require soil/organic substrate for root anchorage and nutrient absorption.
  • Mushrooms are fungal fruiting bodies requiring rich decaying organic matter or soil substrates.
Elimination Heuristic & Exam Approach

Use everyday observation: Mosses commonly thrive on bare damp walls, rocks, and tree trunks without soil. Therefore, 3 must be in the correct combination, eliminating options (a) and (b).

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Question Specifications & Syllabus Mapping

Examination & YearUPSC Civil Services Preliminary Examination 2021 (Q2)
Paper & Marking SchemeGS Paper I • 2 Marks (-0.66 Negative for incorrect response)
Syllabus Subject & TopicEnvironment and Ecology → Ecology & Ecosystems
Official Answer KeyOption (C) — 2 and 3

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Frequently Asked Questions — UPSC Prelims 2021 Q2

What is the official answer for UPSC Prelims 2021 GS Paper I Question 2 (Environment and Ecology)?

The official UPSC answer key for this 2021 Environment and Ecology (Ecology & Ecosystems) question is Option (C): "2 and 3". Correct attempts carry 2 Marks with -0.66 Negative penalty for wrong answers.

Which UPSC Prelims syllabus topic does this 2021 question belong to?

This question belongs to GS Paper I under the subject "Environment and Ecology" and micro-topic "Ecology & Ecosystems". You can explore all repeated questions from Ecology & Ecosystems in Acme AI's 3D Prelims PYQ Realm or practice 50 full-length and sectional tests in the APT Prelims Test Series.

How can I solve this Ecology & Ecosystems UPSC Prelims question using option elimination?

Use everyday observation: Mosses commonly thrive on bare damp walls, rocks, and tree trunks without soil. Therefore, 3 must be in the correct combination, eliminating options (a) and (b).

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