Answer: option D.
Capillaries are part of Circulatory system.
Explanation:
Circulatory system is a system that allows blood , gases, hormones and nutrients to flow to the cells of the body and from the cells to nourish the body,fight against disease and stabilize the body . It consist of heart, blood vessels,lungs.
Capillaries are network of blood vessels that connects and transport blood between arteriole and veinuse. They also transport nutrients and oxygen to tissues and expel waste products.
Capillaries is a network of blood vessels, this it is part of Circulatory system.
