What is the primary function of the circulatory system?

The primary function of the circulatory system is to transport oxygen and hormones throughout the body. This system consists of the heart, blood vessels, and blood, which work in unison to deliver essential oxygen from the lungs to tissues and organs, while also transporting nutrients, hormones, and waste products to and from cells.

Oxygen is crucial for cellular metabolism and energy production, while hormones are essential for regulating various physiological processes, including growth, metabolism, and mood. By efficiently managing this transport, the circulatory system plays a vital role in maintaining homeostasis, ensuring that all bodily functions operate optimally.

While other systems and processes mentioned in the other choices play important roles in the body, they do not represent the primary function of the circulatory system. Structural support is primarily provided by the skeletal system, nutrient absorption mainly occurs in the digestive system, and gas exchange takes place in the lungs but is not the main focus of the circulatory system itself; rather, it is one of the processes supported by it.