A normal M:E ratio is about 3:1. A patient has three times more myeloid precursors than erythroid precursors in the bone marrow because:

a. The body needs more cells to fight infection than to transport oxygen.
b. The life cycle of a WBC is much longer than that of an RBC.
c. WBCs undergo more steps in hematopoiesis than do RBCs.
d. The life cycle of a WBC is much shorter than that of an RBC.

Correct Answer: D