Atmosphere
Frae Wikipedia
The Yird's atmosphere is makkit o the gases in the lift aboot the planet. Thir's hauden aboot the yird bi its gravity. It conteens aboot 78% nitrogen an 21% oxygen, wi trace amoonts o ither gases. The atmosphere fends life on the yird bi absorbin ultraviolet Sun radiation an reducin temperatur differs atween the day an the nicht.