Question

How does the size of chest cavity change during inhalation and exhalation

Answer 1

When diaphram contracts ribs and intercostal muscles move upward and outward and thus the volume inside the thoracic cavity is increased. Air pressure inside the thoracic cavity is less comparing to the outside a medium. So air gushes inside through external nostrils.
When the diaphragm relax, the ribs and intercostal muscles comes to initial position within that time the oxygen is transported to all parts of the body and the carbon dioxide reached into the lungs and is expelled out from Internal nostrils through external nostrils.

Answer 2

Explanation:

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