Biology - Digestion and Absorption Question with Solution | TestHub

Intrinsic factor (Castle's intrinsic factor) is a glycoprotein secreted by the parietal (oxyntic) cells of the gastric glands in the stomach. Therefore, it is a component of gastric juice. It is essential for the absorption of Vitamin ${\text{B}}_{12}$ in the terminal ileum of the small intestine.

Vitamin ${\text{B}}_{12}$ is primarily stored in the liver (although it is synthesised by bacteria, the liver acts as the main reservoir in the human body, which is what the question implies for part A).

Thus, (A) is Liver and (B) is Gastric juice.

Answer: (A) - Liver; (B) – Gastric juice