Answer:
1. B. small intesine
2.A. absorbing
Step-by-step explanation:
When we eat vitamin B12, the R protein, present in saliva and gastric fluids, binds to it. This complex protein bond travels through the stomach with the help of other proteins and factors to reach its final destination.
Once the proteins are in the duodenum (first part of the small intestine), the pancreas secretes a protease that will break the R protein-B12 bond. The B12 will bind to another complex to travel through the ileum (final part of the small intestine) toward the small intestine where the absorption by the enterocyte (intestinal absorptive cells in the inner surface of the small intestine) occurs.
The absorbed vitamin B12 will travel to the liver and the rest will go to other tissues.