Final answer:
Capillary beds, which are part of the body's circulatory system, are supplied by arterioles and drained by venules. The exchange of gases, nutrients, and wastes occurs at these sites before blood returns to the heart.
Step-by-step explanation:
Capillary beds are supplied by arterioles and drained by venules. Arterioles diverge into capillary beds, which are networks of small blood vessels that facilitate the exchange of nutrients, waste, and oxygen with the cells and tissues of the body. These capillary beds contain large numbers of capillaries, with each one having a narrow diameter to allow red blood cells to pass through in single file.
After the exchange at the cellular level, the blood, now higher in carbon dioxide, converges into venules. These venules then connect to minor veins, which eventually lead to major veins responsible for bringing the deoxygenated blood back to the heart. Venules and veins serve as the primary pathways for blood to return from the capillary beds to the heart.
The correct answer to the question is a) Arterioles; Venules.