Which term describes a tough external covering that protects and supports the body of many invertebrates?

Which term describes a tough external covering that protects and supports the body of many invertebrates?

• A. Endoskeleton
• B. External skeleton
• C. Exoskeleton
• D. Hydroskeleton

Answer: (C)

Exoskeleton describes the tough external covering that protects and supports the body of many invertebrates. This external shell provides a hard, protective layer and a rigid frame for muscle attachment, helping defend against injury and water loss while giving the body shape and support. As these organisms grow, they must shed this outer layer and form a larger one, because the rigid covering can’t expand with the body. The material is often chitin in insects and other arthropods, sometimes reinforced with minerals in crustaceans. This distinguishes it from an internal endoskeleton, which supports from inside (as in vertebrates), and from a hydroskeleton, which relies on a fluid-filled cavity for support.

Exoskeleton describes the tough external covering that protects and supports the body of many invertebrates. This external shell provides a hard, protective layer and a rigid frame for muscle attachment, helping defend against injury and water loss while giving the body shape and support. As these organisms grow, they must shed this outer layer and form a larger one, because the rigid covering can’t expand with the body. The material is often chitin in insects and other arthropods, sometimes reinforced with minerals in crustaceans. This distinguishes it from an internal endoskeleton, which supports from inside (as in vertebrates), and from a hydroskeleton, which relies on a fluid-filled cavity for support.