Question

why venis have valves​

Answer 1

Answer:

To allow flow of blood back to heart, lumen inside vein is larger in diameter and to prevent backflow, series of valves are there. Your veins have one-way valves in them to keep the blood moving, and in the right direction. You can help in this procedure simply by making movements. Try to avoid staying in one place or position for too long.

Explanation: