Which of the following pairs of echinoderms [ih-KY-nuh-durms]

have respiratory structures that could be characterized as lungs rather than gills, since they are formed from invaginations of the body surface?

W) Sea star and sea urchin

X) Sea urchin and brittle star

Y) Sea star and brittle star

Z) Sea cucumber and brittle star
Z) SEA CUCUMBER AND BRITTLE STAR