why does the heart automatically adjust the flow of blood to match activity levels? a. extreme activity…

why does the heart automatically adjust the flow of blood to match activity levels? a. extreme activity damages blood cells and the body needs replacements. b. the heart requires more oxygen when exercising. c. it reduces the level of oxygen in the blood. d. organs and muscles require more blood under stress. please select the best answer from the choices provided. o a o b o c o d

why does the heart automatically adjust the flow of blood to match activity levels? a. extreme activity damages blood cells and the body needs replacements. b. the heart requires more oxygen when exercising. c. it reduces the level of oxygen in the blood. d. organs and muscles require more blood under stress. please select the best answer from the choices provided. o a o b o c o d

Answer

Answer:

D. Organs and muscles require more blood under stress.

Brief Explanation:

During increased - activity (stress on body), organs and muscles need more oxygen and nutrients, so heart adjusts blood - flow. Option A is about blood - cell replacement not blood - flow adjustment. Option B is about heart's oxygen need not overall body's need for blood. Option C is incorrect as the goal is to increase oxygen delivery not reduce oxygen level in blood.