In the digestive system, vitamin b12 bound to intrinsic factor (b12-if) is absorbed through the epithelium of the small intestine and delivered into the extracellular fluid on the basolateral membrane of the epithelium by a process called transcytosis. this process begins on the apical surface of the epithelial cell when the b12-if binds to receptors, and is engulfed into the cell. what is the type of membrane transport at the apical surface of the epithelium?

Endocytosis.

Explanation:

Endocytosis may be defined as a type of cellular process by which the substance are brought into the cell. The phagocytosis and pinocytosis are involved in the endocytosis.

Since, the substance has been entered into the cell through transcytosis. The substance is engulfed after binding to its receptor and entered into the cell. This type of membrane transport is involved in the process of endocytosis only.

Thus, the answer is endocytosis.

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