Question

During inhalation

• A. Diaphragm relaxes and rib muscles contract
• B. Diaphragm contracts and rib muscles relax
• C. Both diaphragm and rib muscles relax
• D. Both diaphragm and rib muscles contract

Answer 1

The correct option is D

Both diaphragm and rib muscles contract

The correct option is D:

Explanation of the correct option

1. The process of taking in oxygen-rich air is called inhalation.
2. During inhalation, the diaphragm contracts and flattens, also the rib muscles contract to pull the rib cage upward and outward causing an increase in the volume of the thoracic cavity and the lungs.

Explanation for incorrect options

Option A, B and C:

1. During inhalation, both the diaphragm and rib muscles contract to increase the volume of the thoracic cavity.

Final answer: During inhalation, both diaphragm and ribs contract.