Name the process by which the exchange of gases between an organism and its environment takes place.

The most numerous cells in the epithelium of the bronchus and bronchioles are called:

Give an example of small organism in which the ratio of surface area to volume is high.

The part of the terrestrial leaf on which stomatal opening is seen.

Large amount of water vapour are lost from leaves by which of the following process?

The respiratory system of insects is called:

The water proof layer that protects human skin.

The respiratory organ of fish is called:

Which one of the following is the by-product gas of photosynthesising ?

Guard cells become turgid by actively transporting which of the following ions?