in the chapter review, these are what i dont know..i cant find them definitively online either..
-how is the breathing rate set?
-why do multicelluar organisms require circulatory system
-how does the human circulatory system have a large surface area
-why is the respiratory surface of terrestrial organisms inside the body (rather than outside)
-how does brain moniter the need for oxygen
-if blood pressure is low in veins, how does blood return to heart
-whatare the functions of the pulmonary and aortic semilunar valves
-what vessel is blood pressure highest
thanks alot!!!!!!!