ICSE Class 9 Answered

The importance of the atmosphere is as follows:

• The atmosphere protects the Earth from the solar radiation. It filters the harmful ultraviolet rays of the Sun.
• The atmosphere traps the required heat of the Sun and allows the rest to escape into space, thus maintaining a moderate temperature on the Earth. This ensures the existence of various life forms.
• Due to the friction created in the atmosphere, many meteors and meteorites get burned in the atmosphere, which would have otherwise fallen on to the surface of the Earth.
• Because of the difference in the temperature of the atmosphere, air gets circulated causing winds and the rains. All forms of life depend on these phenomena. 
• Soil absorbs nitrogen and oxygen which is present in the atmosphere. This helps plants to grow.
• The water cycle takes place due to the processes of evaporation, condensation and precipitation. Water vapour, which is a part of the atmosphere, condenses to form clouds resulting in rainfall.