Explain nocturnality in Bat and Earthworm.

Explanation

Nocturnality in Bat
Bats are active at night which is a useful adaptation for them, as flight requires a lot of energy during day. The thin, black wing membrane called patagium may cause excessive heat absorption during the day leading to dehydration.
Nocturnality in Earthworm
Earthworms have no eyes. Instead, they can sense light through the light sensitive cells called photoreceptors present in their skin. They are very sensitive to bright light and therefore stays in burrows during the day and comes out only at night.