Question

What invertebrates have endoskeletons?

Answer 1

If we consider prominent invertebrate animal phyla, the answer will be Porifera and Echinodermata.

Explanation:

Sponges included under Phylum Porifera possess endoskeletal elements in the form of mineralised spicules and organic spongin fibre. Spicules are made of calcium compunds and/or silica. In fact, Poriferans are classified on the basis of their endoskeleton.

In members of Phylum Echinodermata , endoskeleton is made up of calcareous dermal ossicles of various shape and size. Such ossicles also show spines and bumps, all covered by a very thin layer of skin.