Unlike arteries, veins contain valves that ensure blood flows in only one direction. (Arteries don't require valves because pressure from the heart is so strong that blood is only able to flow in one direction.) Valves also help blood travel back to the heart against the force of gravity.

Why are valves an important feature in veins?

The one-way valves in deep veins prevent blood from flowing backward, and the muscles surrounding the deep veins compress them, helping force the blood toward the heart, just as squeezing a toothpaste tube ejects toothpaste.

Why are valves present in heart and veins?

Answer: Valves present in the heart and veins prevent the backflow of blood, that is, flow of blood in the direction opposite to that in which it is flowing.