Question

Why do Platyhelminthes have no alimentary canal

Answer 1

because they have only one opening from the mouth from where the food is taken in and un digested food is passed out there are many parasitic living organisms that live in the intestine of other animals

Answer 2

Platyhelminthes also known as tapeworm or flatworm.

This will not have alimentary canal and the food is totally absorbed with the help of the body surface of this animal.

These are external parasites that live in water as a result they do not have alimentary canal and another reason is that the body of this aquatic animal will absorb the digested food so it has no alimentary canal.

The porous on the body are enough to let the small bits of food to pass.