Answer:
provides gases for respiration and photosynthesis
provides protection from UV radiation and meteorites
stabilizes a habitable temperature
Explanation:
Earth's atmosphere is made up 78% nitrogen, 21% oxygen and trace amount of argon, carbon, water vapor and other gases. The atmosphere provides oxygen which is required for respiration and carbon for photosynthesis. It shield the Earth from UV radiation and meteorites. The atmosphere traps sun heat and maintains stable habitable temperature. Without atmosphere, life would have not been possible. The temperature would be too cold and the surface would have similar to Moon's full of craters.
