ICSE Class 9 Answered
Our atmosphere is about 78% nitrogen and 21% oxygen, with traces of water and carbon dioxide. Jupiter and Saturn are dominated by hydrogen and helium. The thick atmosphere of Venus is about 96% carbon dioxide, and only 3% nitrogen, which is about the same ratio as the thin atmosphere of Mars. Earth is the only planet where Oxygen in found in adequate quantities. The earth also has a blanket of clouds which trap and releases heat maintaing the temperature of the Earth. Planet Venus has such a thick layer of clouds that it prevents the heat from the sun from escaping back into outer space. This makes the venus as the hottest planet in the solar system.
The favourable conditions provided by the earth's atmosphere has helped in the existence of various life forms on the planet.