What are the main components of the atmosphere? How does their composition support life on earth?

The main components of the atmosphere are Nitrogen (78%) and Oxygen (21%). These two gases play a significant role in supporting life on Earth.

1. Oxygen gas helps in burning and breathing. Without breathing oxygen, most living things cannot survive.
2. Nitrogen dilutes the oxygen and slows down the process of oxidation.
3. It is essential for all living things but they cannot use it directly from the atmosphere. Plants obtain it from the soil and animals obtain nitrogen by eating plants or other animals.
4. Nitrogen and Oxygen indirectly help in retaining the necessary warmth on the earth and helps in the circulation of water vapour—the source of rainfall.