In cycle billing, approximately 25 percent of patient accounts are billed each ________.

Peep ______________________________________________________

Fill in the blank(s) with correct word

Which of the following provide antibacterial defense in the airway? 1. IgA 2. IgG 3. Phospholipids 4. Serine proteases

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