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. A B C D.

if your boyfriend is cheating on you, my best advice to you is to dump him, he's only going to drag you down. and if you do, don't fret there's plenty better that know how to treat a person right. i mean honestly, the whole point of a romantic relationship is love, and if you love someone you aren't going to cheat on them. i do believe in second chances, but why would he cheat in the first place? i personally feel that if someone cheats, they ruin any chance they wanted/had with you. i wish you the best of luck with this, hang in there.