Solution:
Digestion is exclusively intracellular in protozoans (e.g., Amoeba) and sponges (e.g., Sycon, Euspongia). Both intracellular and extracellular digestion occurs in cnidarians (e.g., Hydra) and ctenophores (e.g., Pleurobrachia). Digestion in annelids (e.g., Pheretima) is extracellular.
