In animals, a distinct advantage of extracellular digestion over intracellular digestion is that ___.?

I guess b) and d), though neither is completely correct. Most animals still do need a transport system to transport food to cells other than that off the GI tract....and intracellular digestion limits the size of ingested food, but not too much. Protozoans and phagocytes do digest macromolecules other than glucose, so c) is ruled out...and a) takes place in all organisms.