Question

multiple choice question
during inhalation, the external intercostals ______ to increase the transverse dimensions of the thoracic cavity.
relax
contract

Explanation:

During inhalation, the external intercostal muscles contract. This contraction causes the ribs to move upward and outward. As a result, the transverse (lateral - to - lateral) dimensions of the thoracic cavity increase. If the external intercostals relaxed, the ribs would move downward and inward, reducing the thoracic cavity volume, which is part of the exhalation process.

Answer:

contract