1.We wouldn't be able to live
If there was never an atmosphere us,animals,and plants couldn't live here because there is no oxygen.
2.Protects us from meteors
If the atmosphere was not here to protect us we could get hit by a huge rock with craters called a meteor.
3.The temperature changes as you go higher.
As you get higher the temperature changes
first its cold ,then hot ,then warm ,then cool ,last its hot.