Question

resistance in the cardiovascular system
multiple choice
tends to decrease as the diameter of blood vessels decreases.
tends to increase if blood viscosity increases.
dramatically increases blood flow through the circulatory system.
does not occur. if it did, blood would not circulate in the blood vessels.
is directly related to flow (↑ r → ↑ flow).

Explanation:

Resistance in the cardiovascular system is related to blood - vessel diameter and blood viscosity. According to Poiseuille's law, resistance is inversely proportional to the fourth - power of the radius (and thus diameter) of blood vessels, and directly proportional to blood viscosity. Higher viscosity means more resistance.

Answer:

B. tends to increase if blood viscosity increases.