It’s late at night and i’m really confused. i’ve looked through my notes and everything. can someone ? ?

The oxidizing agent our bodies use to obtain energy from food is oxygen (from the air). if you breathe 15 times a minute (at rest), taking in and exhaling 0.5 l of air with each breath, what volume of air do you breathe each day? air is 21% oxygen by volume. what volume of oxygen do you breathe each day?

Select the correct answer from each drop-down menu proteins are

Is dna the same in every cell in the human body explain your answer