1.) Electrons go back into like a lower energy level then would be release a thing called a photon light.
2.) I'm not sure on the correct numbers exactly but if I remember correctly around 70-80 percent is nitrogen, around 20-25 is percent oxygen, 0.9 percent is argon, and 0.1 percent other gases.
3.) Glass is made from sand at least that's one popular element of making sand. one gathered, they are put into a high temperature and would soon make glass coming out of it within time.
