Which term describes the movement of air in and out of the lungs?

• A. Cell
• B. Respiration
• C. Ventilation
• D. Oxygenation

Answer: (C)

The movement of air into and out of the lungs is called ventilation. This term captures the mechanical process—the inspiration that draws air into the lungs and the expiration that pushes air out—driven by pressure changes created by the diaphragm and chest muscles. While respiration can refer to the broader process of gas exchange and cellular energy production, and oxygenation describes how much oxygen enters the blood, neither term specifically names the act of moving air in and out. A cell is unrelated to the mechanics of breathing. So ventilation is the precise term for this air-movement process.