Answer: Capillaries do not have the ability to contract.
Explanation: Capillaries are the smallest and thinnest blood vessels in the body, and they are responsible for the exchange of gases, nutrients, and waste products between the blood and tissues. Capillaries do not have smooth muscle tissue and cannot contract like arteries and veins do. Instead, capillaries rely on the force of blood flow and the pressure of fluids to facilitate the exchange of materials between the blood and surrounding tissues.