Composition of the Atmosphere.
- Atmosphere is composed mainly of nitrogen and oxygen.
- They both make up about 99% of clean, dry air (Nitrogen 78%; Oxygen 21%)
- Other gases like Carbon-dioxide; argon and others comprise 1% by volume.
- Oxygen is the breath of life while nitrogen helps in the growth of living organisms.
- Carbon-dioxide is present in the air in minute amount but is very important.
- It absorbs heat radiated by the earth and keeps the surface of the earth warm.