Question

why do veins have thin walls as closing of stomatal pore

Answer 1

Veins have thin walls because the deoxygenated blood flows smoothly from body parts to the heart.
It contains valves to stop back flow of the blood

Answer 2

veins have thin walls becoz deoxygenated blood flows smoothy and can't flow smoothly in thick walls that's why they have thin walls...
hopefully it will help you...
mark it as branliest plzzzz