Q How different are extracellular and intracellular digestion? What is the evolutionary advantage of extracellular digestion?

Intracellular digestion is that in which the breaking down of macromolecules occurs within the cell. Extracellular digestion is that in which macromolecules are broken down in places outside the cell in the extracellular space, in the surrounds, in the lumen of digestive tubes, and so on.

The advent of extracellular digestion in evolution permissible organisms to benefit from a greater variety of food. The breaking down of larger molecules into smaller ones outside the cell permitted the use of other foods than those that due the size of their molecules could not be interiorized by diffusion, pinocytosis or phagocytosis.