Explain the role of diaphragm in the mechanism of breathing.

A. The diaphragm helps in digestion by secreting digestive enzymes

B. The diaphragm has no role in the mechanism of breathing

C. The diaphragm helps in the process of inhalation and exhalation by changing the volume of the chest cavity.

D. The diaphragm only helps in exhalation and not in inhalation