What is the key function of sphincters found along the digestive system?
a)they selectively allow and stop passage of partially digested food.
b)they control and direct the quantity of food passing through the digestive organs and prevent backward movement of partially digested food.
c)they improve the muscular strength of the organs involved in digestion.

What is a difference between systemic and pulmonary circulation? a. systemic circulation carries oxygenated blood to the lungs and pulmonary circulation carries deoxygenated blood to the body. b. systemic circulation carries deoxygenated blood to the lungs and pulmonary circulation carries oxygenated blood to the body. c. systemic circulation carries deoxygenated blood to the body and pulmonary circulation carries oxygenated blood to the lungs. d. systemic circulation carries oxygenated blood to the body and pulmonary circulation carries deoxygenated blood to the lungs.