Which of the gases have about the same concentration when a person inhales and exhales? O A. nitrogen and argon
O B. oxygen and nitrogen
C. argon and carbon dioxide
OD. carbon dioxide and oxygen

Carbon dioxide and OXygen because the air we breathe out contains 16.4% of oxygen and 4.4% of carbon dioxide.

Explanation:

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.

you can't see the options