Our environment has nitrogen78%,oxyen21% then why our nose only inhale oxygen only , not any other gas. it doesn't has eyes also?

the correct answer is anaphylaxis.

anaphylaxis is a condition caused by insect bites, foods, medications, manifested by tongue swelling, shortness of breath, vomiting, low blood pressure. it sometimes may occur without an obvious reason. it is treated with epinephrine injection.other tretments include antihistamines and steroids,

regulate growth

produce insulin

control bladder

regulate bone calcium

control metabolism

produce adrenaline

this website has a good chart outlining your exact question