Page 1 :
f oxygen int, , called photosynthesis. Cutting of trees can disturb the balance ©, Plants and trees are also, therefore, important as they give us Oxygen., , portant gas and is used by plants for their growth. But they ca, it directly, so they take the help of bacteria which are present in soil to change the form, nitrogen into usable form. This nitrogen is absorbed by the plants for use., , on dioxide is also a very important gas as plants use it to make their food and re’, , dioxide is released by both humans and animals. The amount of carb, s hence, balance Is maintained., , Nitrogen is another im, , Carb, oxygen. Carbon, dioxide released by them is consumed by plant, , However, burning of, solid wastes, trees and, incomplete combustion of, some fossil fuels releases, carbon dioxide which leads, to the presence of excess, of carbon dioxide and, adds to the pollution in, , , , the atmosphere as well as_ | ¢ gases such a, i | r as are, disturbs the natural balance & eed, , of the gases. When the level vw av ——— j, of carbon dioxide increases “ LE NSP, , in the atmosphere, the, temperature of the Earth’s, surface also increases, as carbon dioxide traps, sunrays and does not let, them escape. This is called, global warming. It is due, to this rise in temperature, that the snow in the coldest, parts of the world is melting., As a result, sea level rises,, which triggers floods in the, , low-lying coastal areas., , Global warming, , , , STRUCTURE OF ATMOSPHERE, , The atmosphere is divided into five concentric layers from bottom to the highe te, the atmosphere. These are— troposphere, stratosphere, mesosphere, therm, , “ae O, : OT '