Question

4. Muscular structure that helps to expand and contract the lungs, forcing air in and out
Ribcage
Alveoli
Diaphragm
Nasal cavity

Answer 1

Answer:

diaphragm

Explanation:

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Answer 2

Answer:

diaphragm

Explanation:

Inhaling is an active movement that results from the contraction of a muscle called the diaphragm. The diaphragm is large, sheet-like muscle below the lungsfrom the contraction of a muscle called the diaphragm. The diaphragm is large, sheet-like muscle below the lungs. When the diaphragm contracts, the ribcage expands and the contents of the abdomen move downward. This results in a larger chest volume, which decreases air pressure inside the lungs. With lower air pressure inside than outside the lungs, air rushes into the lungs. When the diaphragm relaxes, the opposite events occur. The volume of the chest cavity decreases, air pressure inside the lungs increases, and air flows out of the lungs, like air rushing out of a balloon.