What does the speaker say about the skin of starfish? [originaltext] Welcome

Welcome to our aquarium. As we begin our tour, the first animal we will see today is the starfish. You probably have seen pictures of the starfish, but in a few minutes you will see some live ones and learn a little about their structure. First of all, starfish are not really fish, they belong to the family of echinoderms which are spiny skinned sea animals, (17)that is, their skin is covered with thorny bumps. Most starfish have five arm-like extensions on their bodies. And so they look like a five-pointed star. But some other kinds have as many as 40 or more arms. Starfish, like other members of the echinoderm family, have what’s called radial symmetry.(18)All that means is that the body part of these animals are arranged around the center, kind of like spokes of a wheel around a hub. One of the special features of the starfish is that(19)it can drop off arms as a defensive reaction, to get away from an attacker, for example. They can then grow new arms to replace the old ones.