Final answer:
True. Contraction of the diaphragm increases the rate of air flow during forced expiration.
Step-by-step explanation:
True. Contraction of the diaphragm increases the rate of air flow during forced expiration. During forced expiration, the diaphragm relaxes and the abdominal muscles contract, pushing the diaphragm up and compressing the lungs, expelling air from the lungs more quickly. This increased rate of air flow helps to empty the lungs more completely during forced expiration.