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

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

The respiratory system of insects is called:

Which part of the organism across around which the gas exchange takes place ?

Write the name of the process of stomatal opening and closure.

The water proof layer that protects human skin.

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?

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

Fish gills are covered by a bony flap called: