Why do veins also have valves? to keep the blood from circulating too fast
to regulate contractions of the heart
to keep the veins from losing blood
to prevent gravity from pulling the blood towards the feet

What is the difference in the phisical activity requirements for achieving healt benefits and performance?

Cammy is cooking hamburger patties for lunch. after a few minutes on the grill, she checks the internal temperature of the patties and finds them to be at 135°f. what should cammy do next?

If scientists are trying to use what they know about hsv to devise a means of protecting other people from being infected, which of the following would have the best chance of lowering the number of new cases of infection? a) vaccinate of all persons with preexisting cases of hsvb) interfere with new viral replication in preexisting cases of hsvc) treat hsv lesions to shorten the breakoutd) educate people about avoiding sources of infection