In general, the walls of arteries are thinner than the walls of veins. true or false?

False.

Artries in general have thicker walls than veins. (thicker tunica media)

This is because artries need to withstand high blood pressure when the heart pumps the oxygenated blood to the rest of the body while veins carry blood (deoxygenated) at lower pressures, hence they are thinner compared to artries

Hope This helps! 

Size and shape of continents