Question

multiple choice question
air moves into the alveoli when the diaphragm and external intercostal muscles _.
o contract
o relax

Explanation:

When the diaphragm and external intercostal muscles contract, the volume of the thoracic cavity increases. This creates a lower pressure inside the lungs compared to the atmospheric pressure outside. As a result, air moves into the alveoli (inspiration). If the muscles relax, the volume of the thoracic cavity decreases, pressure inside the lungs becomes higher than the outside, and air moves out (expiration).

Answer:

contract