Which answer best describes why the walls of arteries are thicker and stronger than other blood vessels?

The walls of arteries are thicker and stronger than those of other blood vessels primarily because they carry blood away from the heart, where the pressure is significantly higher. This high pressure is a result of the blood being pumped directly from the heart, which necessitates a robust structure to withstand the force exerted on the artery walls.

The thicker muscular layer of arteries allows them to be more elastic, enabling them to expand and contract as blood is pumped through them. This elasticity helps maintain blood pressure and ensures efficient circulation throughout the body. In contrast, veins and capillaries do not encounter the same level of pressure, which is why their walls are thinner and less muscular.

Considering the other options, arteries do not carry more blood than veins; rather, they serve different functions. Additionally, arteries do not have valves like veins do; valves in veins are present to prevent backflow due to lower pressure in those vessels. Thus, the structure of arteries is specifically adapted for their role in the circulatory system.