The branchioles end in millions of tiny interconnected cavities called:

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

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

The water proof layer that protects human skin.

Fish gills are covered by a bony flap called:

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

Insects have a protective layer that covers their skin called:

The respiratory organ of fish is called:

Gases are diffused in and out of leaves through small openings called stomata. A stomata is surrounded by two cells called:

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