Chapter 23

True or false? Animal cells do not have walls.

A coelom is a __________ a. type of bristle b. resting stage c. sensory organ d. lined body cavity

Cnidarians alone have a. nematocysts b. a mantle c. a hydrostatic skeleton d. a radula

Flukes are most closely related to ______ . a. tapeworms b. roundworms c. spiders d. horseshoe crabs

Which group has six legs and two antennae? a. crustaceans b. insects c. spiders d. horseshoe crabs

The ______________ are mollusks with a hinged shell. a. bivalves b. barnacles c. gastropods d. cephalopods

A spider's chelicerae ____________ . a. detect light b. inject venom c. produce silk d. eliminate excess water

Which of these groups includes the most species? a. protostomes b. roundworms c. arthropods d. mollusks

The ____________ include the only winged invertebrates. a. cnidarians b. echinoderms c. arthropods d. placozoans

The _______ have a coelom and are radial as adults. a. cnidarians b. echinoderms c. annelids d. placozoans

Match the organisms with their descriptions. a. complete gut, pseudocoelom b. protists closest to animals c. simplest organ systems d. body with lots of pores e. jointed exoskeleton f. mantle over body mass g. segmented worms h. tube feet, spiny skin i. nematocyst producers J. simplest known animal choanoflagellates placozoan sponges cnidarians flatworms roundworms annelids arthropods mollusks cchinoderms