This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: nutrition and digestion, Subject name: Biochemistry
Vit. B12 is absorbed in the 
Select and explain. 
A. Stomach, B. Duodenum, C. Lower jejunum, D. Terminal ileum
D: Terminal ileum
Answer: D: Terminal ileum 
Explanation: One molecule of IF can combine with 2 molecules of B12. This IF-B12 complex is attached with specific receptors on mucosal cells. The whole IF-B12 complex is internalized . It may be noted that B12 is absorbed from the ileum. Ref: DM Vasudevan, page no: 404