Final answer:
Pulmonary ventilation does not involve the diffusion of oxygen; it is the physical movement of air to and from the lungs. External and internal respiration both involve the diffusion of oxygen during gas exchange.
Step-by-step explanation:
The process that does not involve the diffusion of oxygen is pulmonary ventilation (D). Pulmonary ventilation, also known simply as ventilation, is the physical process of moving air into and out of the lungs, without direct involvement in the gas exchange of oxygen. On the other hand, external respiration (A) refers to the gas exchange that takes place in the alveoli, while internal respiration (C) occurs at the level of body tissues, with both involving the diffusion of oxygen.
Among the processes listed, ventilation does not involve diffusion of oxygen. Ventilation refers to the movement of air into and out of the alveoli in the lungs, but it does not involve the actual exchange of gases. External respiration, which occurs in the alveoli, involves the diffusion of oxygen from the air into the blood, while carbon dioxide diffuses from the blood into the air. Internal respiration, which occurs at the tissues, also involves the diffusion of oxygen from the blood into the tissues, and carbon dioxide diffuses from the tissues into the blood.