Physiology Heart, Circulation, and Blood b50ab1a2 Lifespan of fetal RBC is- A Same as adult RBC B 1/4 of adult RBC C 1/2 of adult RBC D 2/3 of adult RBC High-Yield Explanation Ans. (d) 2/3 of adult RBCRef: Ganong, 25th ed/p.555Life span of fetal RBCs is 60 to 90 days. It is about 2/3rd of adult RBCs life span