Read the following examples and choose the appropriate population int…

The correct answer is Option (3) → Commensalism

Population interactions are named by what each species gains or loses. In commensalism one species benefits and the other is neither harmed nor benefited. All three examples fit this pattern. The epiphyte gets a place to grow on the mango branch. The cattle egret catches the insects that grazing cattle stir up. The clown fish is protected by the stinging tentacles of the sea anemone. The mango tree, the cattle and the anemone gain nothing and lose nothing.

Option (1) Mutualism — Incorrect. In mutualism both species benefit, as in lichens or the fig and its pollinating wasp. In these examples the mango tree, cattle and sea anemone get no apparent benefit.

Option (2) Parasitism — Incorrect. In parasitism one species lives on another and harms it (the host). The epiphyte, egret and clown fish do not harm their partners.

Option (3) Commensalism — Correct. Each example has one partner that benefits while the other is not affected. This is commensalism, and the book uses all three as its examples.

Option (4) Competition — Incorrect. In competition both species lose, because they share a limited resource. None of these pairs compete for food or space.

NCERT Extract:
Population Interactions – “… (iv) Commensalism: This is the interaction in which one species benefits and the other is neither harmed nor benefited. An orchid growing as an epiphyte on a mango branch, and barnacles growing on the back of a whale benefit while neither the mango tree nor the whale derives any apparent benefit. The cattle egret and grazing cattle in close association, a sight you are most likely to catch if you live in farmed rural areas, is a classic example of commensalism. … Another example of commensalism is the interaction between sea anemone that has stinging tentacles and the clown fish that lives among them.”