NEET BIOLOGY

Detailed explanation-1: -An echinoderm moves by using many tube feet. Tube feet are small, delicate projections attached along the side of a water-filled tube called a radial canal. Figure 3.85 shows some examples of echinoderm tube feet. Tube feet extend through the small holes in the skeleton to the outside.

Detailed explanation-2: -To sum it up, a sea urchin’s skin is covered with hundreds of little tube feet, which each act semi-independently, for the benefit of the whole animal. And these feet also double as an eye, covering the whole surface of the urchin.

Detailed explanation-3: -The bodies of echinoderms are made of hard calcium-based plates that are often spiny and always covered by a thin skin. The echinoderm skeleton is thus on the inside-called an endoskeleton.

Detailed explanation-4: -Echinoderm skeletons are made up of interlocking calcium carbonate plates and spines. This skeleton is enclosed by the epidermis and is thus an endoskeleton.