UPSC Prelims 2021 · Question 20 of 97

UPSC Prelims 2021 question on Lichen Moss Without Soil

In the 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.

  1. 1 and 4 only
  2. 2 only
  3. 2 and 3
  4. 1, 3 and 4
Show answer

Answer: C. 2 and 3

Verdict

Correct statements: 2 and 3 → Option (c).

Statement by statement

Statement 1 — INCORRECT: A fern is a member of a group of vascular plants that reproduce via spores and have neither seeds nor flowers. Ferns require indirect sunlight, moist soil, and a humid atmosphere. Ferns prefer potting soil with good drainage and high organic content. Hence ferns cannot survive without soil.

Statement 2 — CORRECT: Lichens are a complex life form that is a symbiotic partnership of two separate organisms, a fungus and an alga. They only require an undisturbed surface, time, and clean air. Lichens grow on any undisturbed surface — bark, wood, mosses, rock, soil, peat, glass, metal, plastic, and even cloth. They can survive on a surface without soil.

Statement 3 — CORRECT: Mosses are non-flowering plants which produce spores and have stems and leaves, but don't have true roots. Moss is very low maintenance and needs virtually nothing except shade and moisture to thrive. Hence moss can survive on a surface without soil.

Statement 4 — INCORRECT: A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. Mushrooms can be cultivated hydroponically, but in nature they usually grow on soil/food source.

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