Members of the Cnidarian class __________ never have a medusa stage. 

Which fluke has a smaller, thicker body?

The __________ cavity of Cnidarians serves in digestion and as a site for exchange of respiratory gases and wastes. 

The life cycle of Trichinella is unusual for other nematode parasites in that

The flat shape of Turbellarians help to increase surface area for diffusion.

Worms in class Monogenea infect

Nematodes move with characteristic whiplike movements. They are incapable of localized contractions along the body wall, similar to those observed in earthworms. Which of the following elements of nematode structure explain their particular form of locomotion? Choose all that apply.

The common name for Sabella is

Cnidarians possess a ____________ skeleton.  

Phylulm Platyhelminthes is the first phyla to encompass the levels of organization from cells to organ system.