Which factor is important for any process for adapting the aerobic energy system to exercise? A. the requirement for blood to transform ADP to ATP
B. the frequency for the body to rely on the lactic acid system
C. the efficiency of muscles to remove phosphate from the blood
D. the ability of cardiovascular system to pump oxygenated blood to muscles

Karen is waiting by the lockers before school for her friend richard. they had agreed to look over the history review sheet together to be ready for the test later that day. richard shows up late with uncombed hair and wrinkled clothes. karen: "you're five minutes late and you look like a wreck! " richard: (slams his locker) "you know, i don't have time for this." karen: "fine! figure out the test on your own! "