What type of flatworm has no digestive tract at all?

The type of flatworm that has no digestive tract at all is the tapeworm, which belongs to the class Cestoda. Tapeworms absorb nutrients directly through their skin from the host's digestive system, as they lack a mouth and digestive organs. This adaptation allows them to survive in the intestines of their hosts, where they can thrive by consuming the host's digested food.