At the end of the capillaries, blood vessels widen back into what type of vessel that carries blood back to the heart?

The correct answer refers to the vessels that collect blood from the capillaries and return it to the heart. After the exchange of gases, nutrients, and waste products occurs in the capillaries, the blood begins its journey back to the heart through progressively larger vessels.

Venules are small vessels that initially collect blood from the capillaries. However, venules lead to larger veins. Veins are the vessels that ultimately carry blood back to the heart, featuring one-way valves that help prevent backflow and ensure unidirectional blood flow toward the heart.

Thus, while venules are involved in the process, it is the veins that serve the specific function mentioned in the question, making them the correct answer. Understanding the distinctions among these vessel types is key to comprehending the circulatory system's organization and function.