An example of a reaction to a stimulus is A) a boy smelling a flower
B) eyes blinking due to smoke in the air
C) a person tapping on the shoulder of a friend
D) a loud clap of thunder following lightning

b, acidosis

acidosis is when the human body attempts to return the bloods ph levels back to normal when the blood is acidic

sorry to break it to ya but no one can answer your question it's just

jk but i am serious about the part that most people cant answer it beacuse you did not mention the section you are talking about. but it would if you added some detail and were a bit more specific.