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. ​

The correct answer is C, lichens and mosses. Both are pioneer colonisers that can establish on bare rock where no soil has formed. A lichen is a symbiotic partnership between a fungus and an alga or cyanobacterium: the photosynthetic partner makes food, the fungus holds moisture and anchors to the rock, and the lichen secretes acids that slowly weather the surface. Mosses, which lack true roots, trap dust and moisture in rock crevices and start the process of soil formation.

• Statement 1 (Fern): Ferns need a rooted substrate with soil or humus for water and minerals. They are not pioneers.
• Statement 4 (Mushroom): Mushrooms are fungi that depend on decaying organic matter, such as dead wood or soil, for nutrition. They cannot survive on bare rock.

This is the concept of primary succession, which begins on bare rock exposed by a retreating glacier or cooled lava. For Mains, link it to ecological succession and soil formation under GS-III on environment and land degradation.

Trap: Students choose 1, 3 and 4 by assuming all plants and fungi are equally hardy. They also forget that lichens are not plants at all, even though they are classic pioneer organisms.