Latin-based abbreviation for "both ears" or "each ear":

What is the minimum size pipe typically used to ensure adequate quantities of water through a water distribution system?

A. 6-inch (150 mm) B. 8-inch (200 mm) C. 10-inch (250 mm) D. 12-inch (300 mm)

What impact does initial high altitude exposure have on the alveolar-arterial oxygen difference?

a. It is not affected by changes in altitude b. It is increased c. It is normal but will increase during exercise d. It is decreased