Question

30.a blood vessels and circulation multiple choice

1. the purpose of valves is to:

a. filter debris from the bloodstream
b. ensure unidirectional blood flow
c. move blood through arteries
d. all of the above

Explanation:

Valves in the circulatory system prevent the back - flow of blood, ensuring that blood flows in one direction only. They do not filter debris from the bloodstream (that's the job of organs like the spleen and kidneys), and they are not responsible for moving blood through arteries (which is mainly due to the pumping action of the heart).

Answer:

B. Ensure unidirectional blood flow