Red blood cell production begins with what cell?

Which of the following is the process to track the disposition of blood products from previous donations when supplemental or confirmatory tests on a donor are positive for anti-HIV?

a. Backtrack b. Lookback c. Traceback d. Trackback

For connection to the water main, hydrant specifications require a ____ valve opening.

A. 2 1/2 -inch (65 mm) B. 4-inch (100 mm) C. 5 -inch (125 mm) D. 6-inch (150 mm)