Expiration is a(n):
A. active process that involves the relations of the intercostal muscled and the diaphragm
B. passive process that involves the relaxation of the intercostal muscled and the diaphragm
C. active process that involves the contraction of the intercostal muscled and the diaphragm
D. passive process that involves the contraction of the intercostal muscled and the diaphragm
Answer: B