Final answer:
The Platyhelminthes group does not include roundworms; it includes tapeworms and flukes, while roundworms belong to the phylum Nematoda.
Step-by-step explanation:
The statement that the Platyhelminthes group includes roundworms, tapeworms, and flukes is False. The Platyhelminthes, commonly known as flatworms, include tapeworms and flukes, which are classified under the classes Cestoda and Trematoda, respectively. However, roundworms are part of a different phylum called Nematoda. The Platyhelminthes are characterized by being flat-bodied worms that can be either parasitic or free-living. The parasitic forms, such as tapeworms and flukes, are often of medical importance.