Which of the Following Processes Is NOT a Part of External

Which of the following processes is NOT a part of external respiration?

A) the transportation of oxygen and carbon dioxide between the lungs and body tissues by the blood
B) the exchange of oxygen and carbon dioxide between the lungs and blood by diffusion
C) the exchange of oxygen and carbon dioxide between the blood and tissues by diffusion
D) the movement of air into and out of the lungs by bulk flow
E) the use of oxygen and generation of carbon dioxide by the mitochondria during energy metabolism