Phylum Platyhelminthes (Flatworms)

Where do faltworms live

marine, freshwater, and damp terrestrial habitats

Are all flatworms parasitic

no, but many are such as flukes and tapeworms

What makes flatworms the simplest bilaterians

they are triploblastic but acoelomate (no body cavity)

What tissue layer is unique to triploblasts and what does it form?

mesoderm; gives rise to internal organs and true muscle tissue

What are the four main classes of flatworms

turbellaria, monogenea, trematoda, cestoda