Veins have valves but not artries. Why?

The lumen size Is bigger in vein when compare with artery. Why?

There are valves in the heart between atria and ventricles. Is the purpose of valves in the veins and arteries same?

"Any structure that closes an aperture, and allows one way movement of materials is called vaive. Now let us name the valves that are present in the chambers of the heart". The valve that is present between left atrium and left ventricle can be named as...............

Fertile soils have lots of humus. Why?

Why some animals have scales on their body?

Why is there more pressure in artries than veins?

What heppens if there are no valves in the Heart?

Where are the valves located in human heart? Write their names valves present in human heart.

Where is the valve of The besius in the heart of man? .