What happens to cause air to be exhaled from the lungs? A)The rib muscles contract and move upward
B)The chest cavity expands and grows larger
C)The diaphragm relaxes and moves upward
D)The lungs contract and expand

The answer is C.

Explanation:

When you breathe out or exhale, your diaphragm relaxes and moves up into your chest cavity. As the space in your chest cavity gets smaller, the air rich in carbon dioxide is forced out of your lungs and windpipe, and then out your nose or mouth.

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