Write just a few sentences for an imaginary situation if any of the following gases disappear from the atmosphere.
(a) Oxygen
(b) Nitrogen
(c) Carbon dioxide

(a) If oxygen disappears from the atmosphere, life becomes impossible on earth since oxygen is very essential for the survival of living organisms. Animals and plants take in oxygen from the atmosphere and release carbon dioxide during respiration. It becomes impossible for living organisms to breathe in the absence of oxygen and hence, eventually, the organisms will die.

(b) Nitrogen constitutes a major part of the atmosphere and it does not support burning. If nitrogen gas disappears from the atmosphere, things on earth will burn very fast which may produce disastrous results. Plants require nitrogen for their growth, although it does not absorb nitrogen directly from the air. They consume it in the soluble form either through fertilizers which can be absorbed through the soil. Hence, nitrogen is very important for plants, animals, humans and other organisms to grow properly.

(c) Plants require carbon dioxide to manufacture their own food by the process of photosynthesis. If carbon dioxide disappears from the atmosphere, the plants will not be able to produce their food and oxygen will not be released by them which will disturb the carbon dioxide – oxygen ratio in the atmosphere. Hence, in the absence of oxygen and food, there will be no life on earth.