which blood vessels contain valves that prevent blood from flowing backwards on its way to the…

which blood vessels contain valves that prevent blood from flowing backwards on its way to the heart?\ncapillaries\nalveoli\narteries\nveins

which blood vessels contain valves that prevent blood from flowing backwards on its way to the heart?\ncapillaries\nalveoli\narteries\nveins

Answer

Brief Explanations:

Veins have valves to prevent back - flow of blood as blood pressure in veins is lower and blood needs to flow against gravity towards the heart. Capillaries are for gas and nutrient exchange. Alveoli are in the lungs for gas exchange. Arteries carry blood away from the heart under high pressure and don't need such valves.

Answer:

D. Veins