перевод текста....The earth contains three essential parts, the lithosphere, the hydrosphere and the atmosphere. the atmosphere or air sphere covers the whole of the surface of the earth. the air consists principally of two gases - oxygen and nitrogen. there are about 21 parts of oxygen and 79 parts of nitrogen. Men and nearly all animals must have oxygen or they cannot live. in the atmosphere there is also a little carbon dioxide. now, plants, trees, grass cannot live without carbon dioxide . besides oxygen, nitrogen and carbon dioxide there are small quantities of other gases in the atmosphere; by far the most important is moisture or water vapour. you must picture the Earth as a ball surrounded by an envelope of air - the atmosphere. The coat is at least 50 miles think but the upper layers are pressing down on the lower layers, so the air there is much denser and heavier while in the upper layers it is thin or ''rarefied''