Answer:
b. Capillaries; veins; arteries
Step-by-step explanation:
Capillaries are the blood vessels with very thin walls. They serve as a site for an exchange of substances such as respiratory gases, nutrients, and toxins between the blood and the cells of the tissues. Veins are the blood vessels that mostly pick the deoxygenated blood from the body cells and deliver it to the heart for oxygenation. On the other hand, arteries are the blood vessels that mostly carry the oxygen-rich blood. They pick the oxygenated blood from the heart and deliver it to body cells. Therefore, veins carry blood towards the heart while arteries carry it away from the heart.