Which substances are found on cells surfaces and respond to nerve and hormone signals

Ascientist wants to determine the effect of a new type of gasoline. he fillsone car with normal gasoline and another identical car with the new gasoline. which is the control group? a. the new type of gasolineb. the car with the normal gasolinec. the car with the new gasolinethe amount of gasoline usedd. the amount of gasoline used

When does the circulatory system work with the respiratory system? a. during blood cell formation b. during cellular respiration c. during intestinal digestion d. during a viral infection

What condition is kept close to its set point in osmoregulation? a. body temperature b. platelet count c. blood glucose level d. water balance