Did you know that Mount Everest is about 5.5 miles above sea level? Around 60 million years ago two tectonic plates, the Indian and Asian plates collided making it the highest point on earth. It is nearly impossible to stand on Mount Everest's summit with that much wind and that weather.
Not all mountains have snowcaps. Depends on how much evaporation and how moist it is. It also depends on altitude. If the top of the mountain is not as high it will not be as cold as a mountain that's top was thousands of feet high.
Ozone is a gas molecule made of three oxygen atoms. Ozone is a part of the atmosphere. Ozone is not always great for us humans though. When it gets closer to the earth it can make it harder to breathe. Which hurts trees and crops.