Which is true about breathing while you exercise? A. You should always hold your breathe when you are working hard. B. If you start breathing fast, you should hold your breath to slow it down. C. If you begin to take deep breaths while you exercise, you should stop because it means you are about to pass out. D. The rate and depth of your breathing changes while you exercise to keep a constant level of blood oxygen and carbon dioxide.

What type of lipids are found in all biological membranes?

Which of the four major uses is predicted to change the least by 2020?

Which of the following describes a negative feedback loop? when the heart rate is too high, the body sends hormones that continually increase the heart rate higher. when a pregnant woman is in labor, the body sends hormones that increase the intensity of contractions, which then increases the secretion of the same hormones. when blood sugar is too low, the body sends hormones that raise blood sugar until it reaches a typical level and hormone secretion slows. when a person is jogging, the body sends hormones that continually decrease the rate of oxygen supply to the legs.