Chapter 23

True or false? Animal cells have chitin walls.

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

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

Flukes are most closely related to _____. a. tapeworms c. arthropods b. roundworms d. echinoderms

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

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

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

The _____ include the only winged invertebrates. a. cnidarians c. arthropods b. echinoderms d. mollusks

The _____ move about on tube feet. a. cnidarians c. annelids b. echinoderms d. flatworms

Annelids and cephalopods have a(n) _____ circulatory system. a. open b. closed

A pupa forms during the life cycle of some _____. a. crustaceans c. annelids b. echinoderms d. insects

Match the organisms with their descriptions. _____echinoderms _____mollusks _____sponges cnidarians _____flatworms _____roundworms _____annelids _____arthropods a. complete gut, pseudocoelom b. tube feet, spiny skin c. simplest organ systems d. body with lots of pores e. jointed exoskeleton f. mantle over body mass g. segmented worms h. tentacles with stinging cells