Which Mechanism Best Describes the Process by Which Nutrients Are

Multiple Choice

Which mechanism best describes the process by which nutrients are taken up selectively at the apical surface of the epithelial cells that line the gut and released from their basal and lateral surfaces?

A) Proteins are tethered to the cell cortex.
B) Proteins are tethered to the extracellular matrix.
C) Proteins are tethered to the proteins on the surface of another cell.
D) Protein movement is limited by the presence of a diffusion barrier.