When the diaphragm contracts, the size of the thoracic cavity ________, the pressure inside the thoracic cavity ________, and air flows ________ the lungs.
A) decreases; rises; into
B) increases; drops; into
C) decreases; drops; out of
D) increases; drops; out of

Question

Quizplus · Accepted Answer

When the diaphragm contracts, it moves downwards, which increases the size of the thoracic cavity. This causes the pressure inside the thoracic cavity to drop, creating a pressure gradient that allows air to flow into the lungs. Therefore, option B is the correct answer.

When the Diaphragm Contracts, the Size of the Thoracic Cavity