What term refers to thin-walled blood vessels that are less elastic than arteries?

The term that refers to thin-walled blood vessels that are less elastic than arteries is veins. Veins are responsible for returning deoxygenated blood back to the heart. Unlike arteries, which have thick, elastic walls designed to withstand the high pressure of blood being pumped from the heart, veins have thinner walls and are less elastic. This allows them to function effectively under lower pressure. Additionally, veins often contain one-way valves that help prevent the backflow of blood, ensuring that blood moves in the correct direction toward the heart.

Capillaries are very small blood vessels where the exchange of gases, nutrients, and waste occurs, but they do not fit the description provided as they are not classified as 'thin-walled blood vessels' in the same context as veins. Arteries are primarily responsible for carrying blood away from the heart and have thicker walls to accommodate higher pressure. Venules are the smallest branches of veins and connect capillaries to larger veins, but they are not the main type of vessel that returns blood to the heart in the context of the question.