How is the structural difference between arteries and veins related to their functions?

Correct answer: Arteries withstand high pressure and veins have valves to prevent backflow

Arteries carry blood away from the heart, so they receive blood under relatively high pressure. Their thick, muscular, elastic walls resist this pressure and help maintain flow. Veins return blood at lower pressure; their thinner walls and wider lumen suit this role, while valves stop backward movement, especially against gravity. Therefore A correctly links structure with function. The other options give biologically false roles or deny the differences.