Yawning Is a Modified Respiratory Movement That

Multiple Choice

Yawning is a modified respiratory movement that

A) involves relaxation of the external intercostal muscles.
B) involves contraction of the abdominal muscles.
C) is stimulated by irritation of the nasal mucosa.
D) involves spasmodic closure of the larynx.
E) involves a smooth extended contraction of the diaphragm.