During forced expiration , actively contracting muscles

Options

A. Diaphragm
B. External intercostals
C. Abdominal muscles
D. Diaphragm and intestinal muscle

Answer

C

Explanation

During forced expiration diaphragm (phrenic muscles) and external intercoastal tell muscles to relax so as to decrease thoracic cavity while abdominal muscles contract so as to decrease thoracic cavity. As a result, air pushes from inside to out of wringing.