Which of the following are necessary for normal airway clearance? 1. Patent airway 2. Functional mucociliary escalator 3. Effective cough 4. Normal pulmonary compliance

a. 1 and 4 only
b. 1, 2, and 3 only
c. 2 and 3 only
d. 2 and 4 only

ANS: B
Normal airway clearance requires a patent airway, a functional mucociliary escalator, and an ef-fective cough.