The influence of blood vessel diameter on peripheral resistance is ________.
a. significant because resistance is directly proportional to the blood vessel diameter the only factor that influences resistance
b. significant because resistance is inversely proportional to the fourth power of the vessel radius
c. insignificant because vessel diameter does not vary

The influence of diameter of the blood vessel on peripheral resistance is significant because resistance is inversely proportional to the fourth power of the diameter.

Explanation:

The influence of diameter of the blood vessel on peripheral resistance is significant because the relation between the peripheral resistance and the diameter is given as, resistance is inversely proportional to the fourth power of the diameter. Thus, with small increase or decrease in the value of diameter, the peripheral resistance may vary by a significant amount.