Atmosphere:

Atmosphere is an envelope of the most useful gases that cover the planet earth. It makes our planet unique and enables life to prosper. If  the earth did not have an atmosphere we wouldn't have oxygen to breathe, and the plants wouldn't have carbon dioxide  to make food from. The rays from the sun would have scorched our planet during the day, and temperatures would have fallen far below.the freezing point at night. No living organism would have survived in such a situation. You have already studied how earth's atmosphere has evolved.