AP BIOLOGY

Detailed explanation-1: -An exoskeleton (from Greek éxō “outer” and skeletós “skeleton") is an external skeleton that supports and protects an animal’s body, in contrast to an internal skeleton (endoskeleton) in for example, a human. In usage, some of the larger kinds of exoskeletons are known as “shells".

Detailed explanation-2: -First exoskeletons are made of a protein called chitin while shells are made of calcium compounds. Second, exoskeletons are physically part of the body of the animal they belong to while shells are not considered a body part.

Detailed explanation-3: -An exoskeleton is a hard outer shell that supports and protects the soft tissues of certain animals. Many invertebrates, or animals without backbones, have exoskeletons. These invertebrates include insects, spiders, centipedes, and crustaceans.