Rotifera digestive system consists of which of the following?

• A. Alimentary canal, mouth and anus
• B. Alimentary canal, mouth only
• C. Digestive sac
• D. No digestive tract

Answer: (A)

Rotifers have a complete digestive system, an alimentary canal that runs from mouth to anus. This setup lets food move through specialized regions—mouth, a grinding mastax, stomach, and intestines—before waste exits through the anus. So there are two openings: a mouth and an anus, which is why the description with an alimentary canal and both openings fits best. A digestive sac implies a single opening or a blind gut, and having no digestive tract would be incorrect for rotifers.