The primary function of the circulatory system is to:

The primary function of the circulatory system is to transport nutrients and gases throughout the body. This involves delivering essential substances such as oxygen from the lungs to the tissues and organs, as well as carrying carbon dioxide and other waste products away from the cells to be excreted. Additionally, the circulatory system is responsible for the distribution of hormones and nutrients absorbed from the digestive system, ensuring that every cell in the body receives what it needs to function optimally.

While regulating body temperature, facilitating digestion, and supporting the immune system are important functions that are interconnected with the overall health of the body, they are not the primary roles of the circulatory system. Body temperature regulation is mainly performed by the integumentary and endocrine systems. Digestion is primarily the job of the digestive system, and immune support is largely managed by the lymphatic and immune systems. In summary, the central role of the circulatory system is to ensure the efficient transportation of vital substances necessary for life.