Prelims 2021

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


Select the correct answer using the code given below.
a) 1 and 4 only
b) 2 only
c) 2 and 3
d) 1, 3 and 4
Correct Answer: c) 2 and 3

Question from UPSC Prelims 2021 GS Paper

Explanation : 

Survival of Organisms on Surfaces Without Soil

Lichens and mosses are organisms that are well-adapted to survive on surfaces without soil. These unique organisms have developed special adaptations that allow them to thrive in environments where traditional soil-dependent plants would not survive.


Lichens are symbiotic associations between a fungus and an alga or a cyanobacterium. They are incredibly resilient and can colonize harsh environments, including bare rock, tree bark, and other surfaces where soil is absent or minimal. Lichens can survive in extreme conditions due to their ability to withstand desiccation (drying out) and then rapidly rehydrate when moisture becomes available.


Mosses are non-vascular plants that can grow on a variety of substrates, including rocks, tree bark, and other surfaces where soil is not present. They do not have a traditional root system but instead have structures called rhizoids that help anchor them to the substrate. Mosses can absorb water and nutrients directly through their leaves, which allows them to inhabit environments without soil.

Comparison with Soil-Dependent Plants

In contrast to lichens and mosses, other plants such as ferns and mushrooms generally require soil or organic matter to thrive. Ferns, for instance, are typically soil-dependent and require a substrate rich in organic matter for growth. While some fern species can grow on rock surfaces or as epiphytes on other plants, they usually need some form of soil or organic matter accumulation. Mushrooms, which are the fruiting bodies of fungi, also predominantly rely on organic material such as soil rich in decaying matter for growth.

Therefore, the correct answer is “2 and 3” because lichens and mosses are the organisms most likely to be found surviving on surfaces without soil.

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