An endoskeleton is the primary body support for the
A) annelids, including earthworms.
B) insects, including beetles.
C) cartilaginous fishes, including sharks.
D) bivalves, including clams.
E) crustaceans, including lobsters.

Question

Quizplus · Accepted Answer

Cartilaginous fishes, including sharks, have an endoskeleton as their primary body support. An endoskeleton is an internal skeleton made of bone or cartilage, in contrast to exoskeletons found in arthropods.

The other choices do not have endoskeletons as their primary body support. Annelids and bivalves have hydrostatic skeletons, while insects and crustaceans have exoskeletons.

An Endoskeleton Is the Primary Body Support for the