Question

the microscopic vessels that serve to transfer oxygen and nutrients from the blood into the cells are called—
capillaries.
arteries.
veins.
coronaries.

Explanation:

Capillaries are the smallest blood vessels. They have thin walls which allow for the exchange of oxygen, nutrients, and waste products between the blood and the surrounding cells. Arteries carry oxygen - rich blood away from the heart, veins carry blood back to the heart, and coronaries are related to the blood supply of the heart muscle.

Answer:

A. Capillaries