Question

alveoli are surrounded by...
veins to directly interact with blood.
arteries and veins to directly interact with blood.
capillaries to directly interact with blood.
arteries to directly interact with blood.

Explanation:

Alveoli are tiny air - sacs in the lungs where gas exchange occurs. They are surrounded by a network of capillaries which allows for the diffusion of oxygen into the blood and carbon dioxide out of the blood. Capillaries are the smallest blood vessels and provide a large surface area for efficient gas exchange.

Answer:

capillaries to directly interact with blood.