Where is oxygen come from?

Answer

There is 2 answers, the first one is from trees and planst, they "eat" co2 and "dump" 02 only in daytime because photosyntesis and the second one is fron electrolysis, that means aply electricity to common water, then the positive produces oxigen and the negative produces hydrogen. Sorry about my english, I hope you understand it. If you dont try search both answers to get better results.

• Which degree do you need to become a house painter?
• What is difference between two years p.g. degree of law and LL.m?
• Difference between BE and Btec?