the way an animal's body parts match up around a point or central line

bilateral symmetry


radial symmetry

Parts repeat around center of the body


not identical on both sides of a central line


nerve cells

nerve cords

a bundle of long extensions of nerve cell bodies, lead away from the brain


group of nerve cells


the pouch where food is digested in animals


body cavity in an organism, region where organs are located


tiny openings on the skins surface

collar cells

flagellated cells that push water through a sponge


the large opening at the top of a sponge


replace (tissue or a body part) through the formation of new tissue


small, spike shaped particles of calcium carbonate or silicon dioxide that make up the skeleton of some sponges


invertebrates that have stinging cells and take food into a central body cavity




The cup-shaped body form of a cnidarian that is generally attached to a surface

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!



Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom


Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording