True or False: The walls of the alveoli facilitate the movement of oxygen and carbon dioxide.

The statement is true because the walls of the alveoli are specifically designed to facilitate the exchange of gases—oxygen and carbon dioxide—between the air in the alveoli and the blood in the surrounding capillaries.

The alveolar walls are extremely thin, composed of a single layer of cells known as alveolar epithelium, which allows for optimal diffusion. This structural characteristic enables oxygen to move from the air inside the alveoli into the bloodstream while allowing carbon dioxide, a waste product of cellular respiration, to move from the blood into the alveoli, where it can be exhaled. This gas exchange process is essential for maintaining appropriate levels of oxygen and carbon dioxide in the body, which is critical for overall respiratory function and health.

The other options do not accurately represent the fundamental role of alveoli in gas exchange. Each alveolus is designed for maximal efficiency in this process, emphasizing why the statement is indeed true.