CBSE Questions for Class 7 Geography Air Quiz 2 - MCQExams.com

As we go up the pressure decreases with altitude.

This is because at higher altitudes number of air molecules present are low when compared to those that are present in the lower atmosphere.

Moreover gravitational pull which is responsible for atmospheric pressure is low on the molecules that are away from its surface than those that are closer to it.

The atmospheric layer that supports life is called troposphere. It is the lowest layer of earth’s atmosphere. The troposphere starts at Earth's surface and goes up to a height of 7 Km to 16 km. Almost all weather phenomenon occur in this layer.  

Troposphere is the lower most layer of the earth. It extends from earth’s surface and goes up to a height of 12 km. But its height varies from place to place and from season to season. Almost all weather phenomenon occur in this layer. Air is warmest at the bottom of the troposphere near ground level. But there is a decrease of temperature with increasing height.

The layer present between stratosphere and thermosphere is mesosphere. Height of mesosphere layer is 80-85 kms. It is the layer present between stratosphere and thermosphere. In the mesosphere, temperature decreases as the altitude increases. The upper boundary of the mesosphere is the mesopause, which is the coldest naturally occurring place on Earth.

The layer of earth above mesosphere is thermosphere. It consists of ions due to ultra violet radiations causing photo ionization and hence forms ionosphere.  The temperature in this zone increases with increase in altitude.