Answer:
a) True
Explanation:
Capillaries are the smallest blood vessels, they form networks called "capillary beds" that connect arterioles (small arteries) to venules (small veins). It is at the capillaries that the exchange of substances (nutrients and wastes) between the blood and surrounding tissues occurs.
Capillaries' walls consist of a single layer of endothelial cells. There are different types of capillaries according to their morphology: