The heart rate increases during exercise. This increase in heart rate increases blood flow to the muscles. Explain, as fully as you can, why this increase in heart rate is necessary. pls help I am on a timer, think it is biology but not sure

Getting your heart beating faster than it's resting rate each day trains your body to move oxygen and blood to your muscles more efficiently. This helps your muscles use that fuel more economically as well, and ultimately you move with more ease. In other words, you end up in shape.

Explanation:

answer; i believe the correct answer to the above question is ( friction)