The three most familiar classes of molluscs are the gastropods, one example of which is ; the bivalves, one example of which is ________; and the cephalopods, one example of which is ________.

Cnidarians tend to exhibit both a mobile ________ stage in which their mouths are on ________ of their bodies, and a sessile ________ stage, in which their mouths are

All arthropods share the features of an ________or external material that provides support and protection, and ________, ________ appendages.

Every cell in a flatworm of phylum Platyhelminthes must get its oxygen directly from the environment around it because flatworms lack a ________ system.

Which of the following traits are not shared by all chordates at some point in their lives: notochord, dorsal nerve cord, exoskeleton, pharyngeal slits, sessile living, post-anal tail?

The sponges in phylum Porifera are outliers in the animal kingdom in that, almost alone among animals, their bodies are not composed of ____________ and their body structure lacks the quality of ____________.

All animal phyla except sponges and cnidarians exhibit __________ symmetry in their body plans, meaning a symmetryin which ______ of their body are mirror images of one another.

A coelom is an internal ___________ possessed by almost all animals except sponges, jellyfish, and flatworms.

A feature common only to animals is that all animals pass through a ____________ stage in their ____________ development.

Four other features that all animals share are that they are ____________ for at least part of their lives, ____________, __________, and their cells do not have

Vertebrates make up a ____ portion of the animal kingdom.