By age 20, a person's bones stop growing
a. bone-forming cells are no longer present.
b. less calcium is present in the body.
c. hormones cause the growth centers at the ends of the bones to degenerate.
d. bone cells receive less oxygen and nutrients at that time.

Why is it important to know the difference between stressors we can control and those we can't? a)we can neglect the effects of uncontrollable stressors and focus on the controllable ones. b) it gives us a sense of power to know that we have control over certain stressors. c)it us come up with strategies to reduce the effects of a stressor.

Mark's girlfriend dropped him off at a party, and then she went to visit her best friend two blocks away. when mark called his girlfriend to get a ride home, he could tell she had been drinking. what is mark's best plan of action? ride home with someone else and let his girlfriend drive herself get a friend to take him to his girlfriend's car so he can drive them both home ask his girlfriend to drive to the party, and then mark will drive them both home let his girlfriend drive them home slow to avoid getting pulled over

Check all that occur during ventricular systole. a. the av valves open to allow blood to enter the ventricles from the atria. b. the av valves open to allow blood to enter the ventricles from the atria. c. the semilunar valves remain closed throughout systole to prevent backflow of blood into the ventricles. d. the semilunar valves remain closed throughout systole to prevent backflow of blood into the ventricles. e. the semilunar valves open to allow blood to flow into the large arteries. f. the semilunar valves open to allow blood to flow into the large arteries. g. the av valves close to prevent backflow of blood into the atria.