Which of the following statements is true about the worm phyla? A. Annelida, Platyhelminthes, and Nematoda all have animals with a coelom
B. Annelida and Nematoda phyla are the simplest of all worms while Platyhelminthes are complex worms
C. many annelids are parasites, but flatworms and roundworms help fertilize the soil
D. most annelids are free-living animals, but most flatworms and roundworms are parasites