In order to maintain homeostasis, the systems of the human body work together to supply our cells with needed substances. Which of the following statements BEST describes how the human body responds to exercise? * A. The digestive system carries nutrients to the muscles of the muscular system to help contract and warm the muscles.

B. The circulatory system delivers oxygen to the cells faster, to enable the muscles to convert energy at an increased rate.

C. The skeletal system produces more blood cells that circulate through the blood vessels, increasing blood flow.

D. The muscular system moves the bones to allow cellular respiration to take place.