This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Lifespan of fetal RBC is ? 
Select and explain. 
A. Same as adult RBC, B. 1/4 of adult RBC, C. 1/2 of adult RBC, D. 2/3 of adult RBC
D: 2/3 of adult RBC
Answer: D: 2/3 of adult RBC 
Explanation: Ans. is 'd' i.e., 2/3 of adult RBC"Life span of fetal RBC is about 2/3' of the adult RBC, i.e. about 80 days."