Answer:
The atmosphere of the earth is comprised of different gases forming various layers that protect from the harmful ultraviolet radiations released from the sun. It is comprised of the following gases-
1) Nitrogen- It makes up about 78% of the earth's atmosphere, being the most abundant gas. It is denoted by N₂.
2) Oxygen- It is the second most abundant gas in the atmosphere denoted by O₂. It makes up about 21% of the atmosphere and is the most essential element for lives to exist. Oxygen is required in order to burn fossil fuels.
3) Argon (Ar)- It is the third abundant gas, forming approximately 1% of the atmosphere. It is an inert gas.
4) Carbon dioxide (CO₂)- It is the fourth abundant gas that is composed of 0.03% of the atmosphere. This gas is very important because it controls the earth's global temperature. A small increase in this content can lead to a rise in the average temperature.
The remaining amount is composed of other gases including water vapor.