The ___________ is a strong wall of muscle that contracts to create a suction in the chest to draw in air and expand the lungs. When the muscle relaxes, the chest cavity decreases and the air is pushed out.
(1 point)

Pulmonary artery

Breathing apparatus

Trachea

Diaphragm

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Diaphragm

The diaphragm is the strong muscular wall that contracts downward to expand the chest (drawing air in) and relaxes upward to decrease chest volume and push air out.