The atmosphere acts as a blanket or glass house as it (a) protects the earth from the harmful ultraviolet rays of the sun. (b) It allows the incoming solar radiation to pass through; (c) It absorbs 14% of the incoming solar radiation, thus prevents the earth from becoming too hot in the daytime, (d) The water vapor and carbon dioxide in the lower layer retains the outgoing terrestrial radiation from the earth, thus preventing the earth from becoming too cold at night time. The extremes of temperature between day and night would be much greater if there was no atmosphere, (e) the differential heating up of the atmosphere by the sun’s ray’s produces circulation of air leading to winds, clouds, precipitation and other weather phenomenon. The variation in climate on the earth is respon­sible for diversity in the distribution of plants and animals.