I believe the answer is C.
Answer:
use dictionary to find out meanings and also take help from TB material
Answer:
I believe the answer is B.
Answer:
The reason is because the heart requires more oxygen when exercising. Several physiological events happen to increase the blood flow and therefore oxygen flow to that muscles,including the heart.
Also the volume of blood that the heart pumps out is maintained so that the body organs receive the necessary amount of oxygen and nutrition, because if it didn't adjust the flow of blood to match activity level, you will be insufficient. Either output method will be lower than needed.
