Ovulation theoretically occurs a. at the beginning of the menstrual cycleb. in the estrogen if phase of the menstrual cycleb. at the end of the menstrual cycled. 14 days prior to the onset of menses

the more fit you are, the faster the recovery. your heart rate drops most sharply in the first minute after you stop exercising; it should then fall about 20 beats a minute—a drop of less than 12 beats a minute is considered abnormal. this “recovery heart rate” is measured as part of an exercise stress test.

b) the heart is a pump made of muscle and that is difficult to grow in the lab.