How The Atmosphere Protects Us? What Is The Composition Of Air?

Among all the plants of the solar system, only the earth has the right kind of atmosphere in which plants and animals can live. It has oxygen which we use to breath. It has carbon dioxide which plants use to make to food. The atmosphere stops a large part of the heat of sun from reaching the earth. If there was not atmosphere, we could be roasted by the heat of the sun during the day. At night, the atmosphere stops the heat of the earth from escaping out into space. Without the atmosphere it would become freezing cold at night.
The stratosphere contains a layer of a gas called ozone. It prevents harmful rays of the sun form reaching the earth. These rays are dangerous and can cause eye problems and skin cancer.

Air contains different gases. A colorless gas with no smell, called nitrogen, form more then three-fourth (about 78%) of air. About one fifth (21%) is the gas oxygen. Other gases such as argon, carbon dioxide and a few others form the remaining small portion (1%). Only three-hundredth (0.03%) is carbon dioxide. But this is enough for plants to make food. Beside these gases, air also contains dust, smoke and water vapors. The amount of these present in air varies form place to place and time to time.