NEET BIOLOGY

Detailed explanation-1: -Flatworms (phylum Platyhelminthes) are simple animals that are slightly more complex than a cnidarian. Roundworms (phylum Nematoda) have a slightly more complex body plan. Segmented worms (phylum Annelida) are the most complex animals with worm-like body plans.

Detailed explanation-2: -flatworm, also called platyhelminth, any of the phylum Platyhelminthes, a group of soft-bodied, usually much flattened invertebrates. A number of flatworm species are free-living, but about 80 percent of all flatworms are parasitic-i.e., living on or in another organism and securing nourishment from it.

Detailed explanation-3: -Phylum Platyhelminthes is composed of the flatworms: acoelomate organisms that include many free-living and parasitic forms. Most of the flatworms are classified in the superphylum Lophotrochozoa, which also includes the mollusks and annelids.

Detailed explanation-4: -Class Turbellaria (turbellarians, flatworms) Class Monogenea (parasitic flukes) Class Trematoda (parasitic flukes) Class Cestoda (tapeworms)