Which one of the following shows a unique relationship with an insect that has coevolved with it and that is the only insect that can pollinate this tree?

Answer: (a) Fig

Each fig species is usually pollinated by its own fig wasp, which breeds inside the fig — a classic obligate mutualism.

The idea

A fig is not a simple fruit. It is a closed ball with hundreds of tiny flowers on the inside. No bee, bird or wind can reach them. Only a tiny female fig wasp can squeeze in through the small opening.

Wasp enters the fig with pollen → Pollinates the flowers and lays eggs → Young wasps grow inside → New females leave carrying pollen → They enter another fig of the same species

Why the others are wrong

(b) Mahua flowers are open, fleshy and sweet. Bats, birds and many other animals feed on them and carry the pollen, so no single insect is needed.

(c) Sandalwood has small open flowers visited by bees, flies and other insects.

(d) Silk cotton has large, open red flowers full of nectar. Birds and bats pollinate them.

Also know

Each kind of fig usually has its own kind of wasp: the tree cannot set seed without the wasp, and the wasp cannot breed without the fig. This is obligate mutualism produced by co-evolution. Banyan and peepal are figs. Because some fig tree is in fruit at any time of year, figs are a keystone food source in forests.