Chapter 23

\(\mathrm{A}(\mathrm{n})\)________ develops from a two-layer embryo. a. sea star b. sea anemone c. butterfly d. earthworm

A great adaptive radiation of animals that occurred during the ________ gave rise to modern animal lineages. a. Precambrian b. Ediacaran c. Cambrian d. Jurassic

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

Cnidarians alone have ________. a. cnidocytes b. a mantle \(c\) a hydrostatic skeleton d. a radula

Flukes are most closely related to ________. a. tapeworms b. roundworms c. leeches d. echinoderms

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

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

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. mollusks

The ________move about on tube feet. a. cnidarians b. echinoderms c. annelids 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 b. echinoderms c. annelids d. insects

Match the organisms with their descriptions. ________echinoderms ________mollusks ________sponges ________cnidarians ________flatworms ________roundworms ________annelids ________arthropods a. tubular gut, pseudocoelom b. spiny skin c. simplest organ systems d. lots of pores, no symmetry e. jointed exoskeleton f. mantle over body mass g. segmented worms h. tentacles with stinging cells