Asked by Brooks

Lev has been holding his breath for 15 seconds. As he exhales and releases the breath, what is happeningin his chest cavity?
A. His respiratory muscles contract
B. His respiratory muscles relax
C. His ribcage becomes rigid and enlarged
D. His ribcage flexes to allow his lungs to expand

All Answers 1

Answered by GPT-5 mini AI
B. His respiratory muscles relax.

When he exhales passively, the diaphragm and external intercostals relax, the diaphragm rises and the ribcage moves down/inward, thoracic cavity volume decreases, intrapulmonary pressure rises, and air is expelled.