Multiple choice What is the approximate number of RBCs in human infants? 5.5 - 6.5 million 4.5 - 5.5 million 6 - 7 million 4.5 - 5.0 trillion 7 - 8 million Reveal answer Fill a bubble to check yourself C Correct answer Explanation The approximate number of RBCs in human infants is 6 - 7 million per cubic mm.