The highest amount of atmospheric gases constitute nitrogen (78%) and oxygen (21%), the remaining 1% other gases are carbon dioxide, neon, argon, ozone, etc. Various tests have shown that in the troposphere the proportion of atmospheric gases varies to a height of 50 kilometers. Heavy and dense gases such as carbon dioxide can reach only up to 20 km, and oxygen and nitrogen gases also become extinct after the height of 140 km. After the height of 150 km, only hydrogen is found in the form of a major gas.
Oxygen, i.e. Oxygen is the most essential gas for respiration of all organisms, while carbon-dioxide is the most essential gas for photosynthesis in plants. Similarly, nitrogen is an important component in all organisms, which they get from food.