What is the primary function of the cardiovascular system?

The primary function of the cardiovascular system is to transport oxygen, nutrients, hormones, and waste products throughout the body. This system is essential for maintaining homeostasis, as it facilitates the delivery of vital substances to tissues and organs. Oxygen and nutrients are carried to cells, enabling them to perform their functions, while carbon dioxide and other waste products are removed for excretion.

The cardiovascular system consists of the heart and a network of blood vessels, including arteries and veins, which work together to ensure efficient circulation. This continuous flow of blood supports not only cellular metabolism but also the functioning of other systems such as the immune system and thermal regulation. Transporting hormones is crucial for regulating various physiological processes, including growth and metabolism.

In contrast, the other options do not encapsulate the main role of the cardiovascular system as effectively. While maintaining body temperature is a function that occurs through the cardiovascular system by regulating blood flow to the skin, it is not its primary purpose. Circulating blood only within the heart does not address the system's overall function, and supporting immune function is part of the overall biological processes that involve various systems, not a direct primary role of the cardiovascular system itself.