Question

Which of the following describes the properties that allow capillaries to exchange gas between blood cells and surrounding tissue?

a. Capillaries are short vessels with thin walls that create strong pressures forcing gas-infused blood to diffuse to the surrounding tissue.
b. Capillaries have thin walls and narrow diameters so that blood cells come close to the thin walls, across which gases can diffuse to surrounding tissue.
c. Capillaries have valves along their walls that allow blood cells to move through them to surrounding tissue, where gas exchange can occur.
d. Capillaries regulate the pressure of blood within them so that a steady stream of gas-infused blood cells passes into the surrounding tissue.

Answer 1

The correct answer is option b.

Step-by-step explanation:

Capillaries refer to the fine bifurcated blood vessels and are the minutest blood vessels exhibiting a diameter of about 5 to 10 micrometers. They are about one-celled thick, that is, they are very thin-walled. They are regarded as the location of exchange of substances between the blood and the cells. The smaller molecules like gases, water, and ions are interchanged via simple diffusion, while the bigger molecules like amino acids, glucose, albumin, and others are passed via active or passive transport process.

Answer 2

I think the correct answer from the choices listed above is option B. The properties that allow capillaries to exchange gas would be that capillaries have thin walls and narrow diameters so that blood cells come close to the thin walls, across which gases can diffuse to surrounding tissue.