<prompt> Intrinsic factor is required for absorption of -Folic acidVitamin B12Vitamin B2Vitamin B6  <response>: Ans. is b i.e., Vitamin B12 o Vitamin B12 cyanocobalamine is absorbed in the ileum, o Intrinsic factor of castle is necessary for its absorption. o IF is secreted by oxyntic cells of stomach. In the lumen of the small intestine, IF forms a complex with vitamin B12. o Vitamin B12-IF complex binds with a specific receptor on the surface of the epithelial cells of the ileum. o Vitamin B12 is transported into the enterocytes leaving behing IF at the brush border. 