Question

1) Oxygen from air is used for and burning​

Answer 1

Answer:

In order to burn this fuel, oxygen is needed, as it is with any fire. The waste products from the combustion process are water and carbon dioxide. Thus, we breathe because oxygen is needed to burn the fuel (sugars and fatty acids) in our cells to produce energy The air we breathe contains about 21% oxygen.

I hope it will help you