A Plathyhelminth is an;
Animal, an Invertebrate to be more precise (no backbone)
Has a flat body, in fact another name for Plathyhelminth is a flat worm.
Segments present.
May be free living or parasitic although most behave as parasites.
For example: Tape worm and fluke.
"They are neither. This is because they do not have a true gut. Protostomes are annelidids(earthworms) Mollusca(clams, snails, octopus, etc.) and arthropods which are your insects or spiders. The only Deuterostomes are Phlya Chordota and Echinodermata." The above answer is incorrect. Plathyhelminthes are protostomes. There are many, MANY groups of protostomes besides annelids, molluscs, and arthropods.
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