The system that includes both the heart and lungs is known as what?

The term "cardiopulmonary" specifically refers to the integrated functions of both the heart (cardio) and the lungs (pulmonary). This system is vital for the circulation of blood and the exchange of oxygen and carbon dioxide within the body. The heart pumps oxygenated blood from the lungs to the rest of the body, while the lungs are responsible for oxygenating the blood that returns from circulation.

Understanding that the focus of the question is on the specific collaboration between the heart and lungs makes "cardiopulmonary" the precise choice. The other terms, such as "cardiovascular," refer broadly to the circulatory system involving the heart and blood vessels, while "pulmonary" focuses solely on the lungs and breathing. "Circulatory" encompasses a wider array of components, including blood vessels and various fluid dynamics, but does not pinpoint the relationship between the heart and lungs as "cardiopulmonary" does.