Question

Which of the following blood vessels are small, thin, and porous enough to exchange substances at the tissue level of organizationA) arterioles B) capillaries C) venules D) small arteries E) veins

Answer 1

The correct answer is B. Capillaries

Step-by-step explanation:

"Capillaries are the smallest blood vessels. If the circulatory system is a series of roads, capillaries would be the side streets and alleys that reach the individual buildings in the city. Most capillaries are so narrow that blood cells travel through them single file. The thin walls of these narrow vessels allow gas exchange to occur."

There are questions very similar to this, capillaries are also the answer for those.

Answer 2

Answer: The correct answer is capillaries

Step-by-step explanation:

capillaries are tiny branched blood vessels that links arterioles to venules and allows exchange of nutrients and gases between the blood and its surrounding tissues