Which of the following are common mechanisms used to control blood flow to different areas of the body?
a. changes blood viscosity
b. vasodilation of blood vessels
c. both vasodilation and vasoconstriction
d. vasoconstriction of blood vessels
e. changing vessel length

Both vasoconstriction and vasodilation.

Explanation:

The mechanism that controls the blood flow to various parts of the body is vasoconstriction and vasodilation.

Vasoconstriction can be defined as the phenomenon in which blood vessels  decrease in diameter to decreases, the pressure in the blood vessels also increases which in turn increases the blood flow.

Vasodilation can be defined as the phenomenon in which the diameter of blood vessels increases and the pressure in the blood vessels decrease and blood flow decreases.

This increases and decreases the blood flow so as to make the blood reach each and every part of the body.

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