oxygen and carbon dioxide move down their concentration gradients by diffusion. Explain how the blood flow at an alveolus ensures there is a high rate of diffusion for both gases following the inhalation

Explanation:

The partial pressures of oxygen and carbon dioxide change as blood moves through the body. In short, the change in partial pressure from the alveoli to the capillaries drives the oxygen into the tissues and the carbon dioxide into the blood from the tissues.

it would lead to upper respiratory infections and pneumonia.

oxygen +1 most likely