This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
In sickle cell anemia 
Select and explain. 
A. Glutamate replaces valine, B. Valine replaces glutamate, C. Valine replaces aspaate, D. Aspaate replaces valine
B: Valine replaces glutamate
Answer: B: Valine replaces glutamate 
Explanation: Sickle cell anemia is caused by mutation in the beta globin chain, that changes the amino acid glutamate to valine in the 6th position of beta globin chain of HbRef: Textbook of medical physiology by N Geetha, 3rd edition, page no. 94