Answer:
veins: resistance vessels
Explanation:
Arterioles are known as resistance vessels as they regulate the resistance to blood flow by altering their diameter. The resistance regulates the supply of blood to the respective capillaries.
Resistance to blood flow is due to friction between the walls of the blood vessels and blood. The friction is increased with vasoconstriction and decreased with vasodilation.
Arterioles regulate the resistance to blood flow by contraction and relaxation of their smooth muscles and thereby increasing and decreasing the friction respectively.
