Question

part a
which tissue in the walls of blood vessels allows for regulation of vessel diameter?
cardiac muscle
epithelial tissue
neural tissue
smooth muscle

Explanation:

Smooth muscle in blood - vessel walls can contract or relax. This contraction and relaxation change the diameter of the blood vessels, a process called vasoconstriction and vasodilation respectively. Cardiac muscle is specific to the heart, epithelial tissue forms linings and coverings, and neural tissue is related to the nervous system and not directly for vessel - diameter regulation.

Answer:

Smooth muscle