Question

Stomata perform the function of
A. Gaseous exchange
B. Oxygen evolution
C. Carbon dioxide evolution
D. Carbon dioxide absorption

Answer 1

Hint: Respiration is a must natural process occurring in all the living organisms. There are different methods to respire but the basic principle is to exchange the gases. One of the gases is released in the atmosphere while another is absorbed from the same. Plants and animals have developed a very interdependent system of respiration.

Complete answer:
Stomata are the small openings or pores at the abaxial surface of the leaves. Their major function is to regulate the water amount by its movement via transpiration. The excess of water is lost by transpiration.
The second main function of the stomata is to exchange the gases. We know plants inspire carbon dioxide and release oxygen. So this exchange takes place by stomata.
Option A: Gaseous exchange: The stomata helps in the exchange of gases by opening and closing of pores. It allows the carbon dioxide to enter and oxygen to leave the surface of a leaf.
Option B: Oxygen evolution: the oxygen is released out by the leaves which are inhaled by the animals and humans. But the stomata do not only release oxygen.
Option C: Carbon dioxide evolution: carbon dioxide is needed by the leaves to conduct photosynthesis, so it is the substrate that is inhaled by them via stomata.
Option D: Carbon dioxide absorption: carbon dioxide is inhaled or absorbed by the leaves but is not their sole work. They release oxygen and absorb carbon dioxide.

So the answer is option A: Gaseous exchange.

Note: Stomata looks like doughnuts. They have guard cells which make this pore open or close. They are numerous. They do the two most important works or mechanisms of leaves- transpiration and photosynthesis. Their size and density vary among the species.