Question

Which phrase correctly identifies one way that veins function in the circulatory system?

Blood is carried under high pressure in veins.
Gas exchange takes place over the thick walls of veins.
Blood is prevented from backflow by valves in veins.
Nutrient exchange takes place over the thin walls of veins.
Veins carry blood back to the heart--often against the pull of gravity.

Answer 1

It’s E. Veins carry blood back to the heart often against the pull of gravity

Answer 2

Blood is prevented from backflow by valves in veins.

Step-by-step explanation: