What comprises the annelid digestive system?

• A. Alimentary canal with gizzard, mouth and anus
• B. Gastrovascular cavity
• C. Digestive sacs
• D. No digestive system

Answer: (A)

Annelids have a complete digestive system: a through tube from mouth to anus, called the alimentary canal. It usually includes a mouth, pharynx, esophagus, a crop for storage, a muscular gizzard for grinding, and an intestine where digestion and nutrient absorption occur, with wastes exiting through the anus. This setup—a true tube with two openings and specialized regions—is what the option describes when it mentions an alimentary canal with a mouth, gizzard in some species, and an anus. In contrast, a gastrovascular cavity is a single-opening, blind-sac arrangement found in some simpler animals, and saying there is no digestive system contradicts what annelids have.