Atmosphere is important for life due to following reasons:
(i) It keeps the average temperature of the Earth steady during the day and even throughout the year.
(ii) It prevents the sudden increases in temperature during the daylight hours.
(iii) The gases it contains are required for sustaining life on Earth. These gases are:
(a) Oxygen which is required for respiration by all living organisms.
(b) Carbon dioxide is used in photosynthesis by plants to synthesize food.
(c) Nitrogen provides inert atmosphere and an important component of proteins.
(iv) A thick layer of ozone (in stratosphere) of atmosphere, filters the harmful UV radiations reaching the Earth. The UV rays produce harmful effects on all living organisms.
