JLAB Academic Practice Test

The system that consists of the heart and blood vessels is the circulatory system. This system is responsible for transporting blood throughout the body, delivering essential nutrients and oxygen to cells while removing waste products like carbon dioxide. The heart acts as a pump, circulating blood through a network of arteries, veins, and capillaries.

In contrast, the respiratory system is primarily involved in the exchange of gases—specifically, the intake of oxygen and the expulsion of carbon dioxide. The lymphatic system plays a critical role in immune function and the maintenance of fluid balance, but it is not centered on the heart and blood vessels. The muscular system involves the skeletal muscles that facilitate movement but does not directly include the organs related to circulation. Understanding the distinct functions of these systems helps clarify why the circulatory system, with its core components of the heart and blood vessels, is the correct answer.