What is a primary function of the circulatory system?

The circulatory system has several critical roles, but one of its primary functions is to transport oxygen and nutrients throughout the body. Blood, which is the main component of the circulatory system, carries oxygen obtained from the lungs and nutrients absorbed from the digestive tract to cells in various tissues. This process is essential for cellular respiration, which provides the energy required for all bodily functions.

Additionally, the circulatory system also plays a key role in removing waste products, such as carbon dioxide and metabolic by-products, from tissues and transporting them to the appropriate organs for elimination, such as the lungs and kidneys. Thus, the efficient transport of oxygen and nutrients is fundamental to maintaining the health and functionality of all body systems.

While the other options describe important functions related to the circulatory system, they do not represent its primary role in supporting life and cellular function as directly as the transportation of oxygen and nutrients does.