What are disadvantage of incomplete alimentary canal ? And also discuss the advantage of complete alimentary canal.
Complete alimentary cycle : In this, mouth and anus or clocal aperture are present. E.g. from Nematodes to Chordates

Incomplete alimentary cycle : In this, only ore opening i.e. mouth is present. E.g. flatworms

Disadvantage of incomplete alimentary canal.

1. Waste food must be expelled before taking the next food, otherwise there would be mixing of both.

2. The incomplete digestive tract cannot store the food.

3. It is less efficient because it serves as the function of circulatory system.

Advantage of complete alimentary canal.

1. There is no chance of mixing in digested food and waste food, because the opening for ingestion and egestion are separate.

2. For circulation of absorbed food there is circulatory system.

3. It is more efficient.