Which of the following statements best describes the circulatory system?

The circulatory system is primarily responsible for transporting blood throughout the body, which is essential for the delivery of oxygen and nutrients to the cells. This system is vital for maintaining the body’s metabolic functions, as it not only provides the necessary components that cells need to generate energy but also plays a critical role in the removal of waste products such as carbon dioxide and other metabolic wastes. This transport function ensures that all tissues receive adequate supplies for their needs while also enabling the elimination of harmful substances, thereby maintaining homeostasis within the body.

The other statements pertain to different body systems or functions. The nervous system is responsible for controlling voluntary and involuntary activities, the muscular system provides shape and assists with movement, and the respiratory system is tasked with taking in oxygen and delivering it to the blood. Each of these functions is essential, but they do not describe the primary role of the circulatory system, which is why the first option accurately represents its key functions.