Question

In which layer, most of the atmospheric air is present?
A: Troposphere
B: Stratosphere
C: Mesosphere
D: Thermosphere

Answer 1

Hint: The earth’s atmosphere is composed of seven layers. The layer nearest to the earth’s surface contains most of the atmospheric air. It contains around $75\mathrm{\%}$ of the total atmospheric air which helps in sustaining life on earth.

Complete step by step answer:
As we know the earth’s atmosphere has $7$ layers . The name of the layers as we go up the atmosphere starting from the earth’s atmosphere are-
1)Troposphere
2)Stratosphere
3)OzoneLayer
4)Mesosphere
5)Thermosphere
6)Ionosphere
7)Exosphere.
Now we can see that the Troposphere is the closest to the earth , so it will contain most of the atmospheric air present in the earth’s atmosphere. Troposphere contains $75\mathrm{\%}$ of the total air of the atmosphere.

So, the correct answer is Option A .

Additional Information:
The troposphere layer extends upto $8km$ to $14.5km$. It is the most dense layer of the atmosphere. It contains three quarters of the mass of earth’s atmosphere. The main constituents of the troposphere are nitrogen, oxygen, carbon dioxide, traces of argon, hydrogen , ozone and other gases. The clouds are present in the troposphere because it is closest to the earth’s surface. The lower part of the troposphere is warmer as compared to the uppermost layer of the troposphere. The ozone layer protects the earth from harmful rays ( Ultraviolet rays ) which come from the sun.

Note:
The upper layer of the troposphere is very cold and turbulent . It is difficult and very risky to fly aeroplanes in such turbulent environments. For these reasons it is preferred to fly aeroplanes in the lower layer of the Stratosphere which is just above the Troposphere.