What is the term for a skeleton that is secreted external to the epidermis of the body?

The term for a skeleton that is secreted external to the epidermis of the body is exoskeleton. An exoskeleton is composed of a hard outer structure that provides both protection and support to the organism and is commonly found in invertebrates such as insects, arachnids, and crustaceans. This structure is typically made of chitin or calcium carbonate, allowing it to protect the organism’s internal organs from environmental hazards and physical injury, while also providing a rigid framework for muscle attachment and movement.

In contrast, an endoskeleton is an internal skeletal structure, like that found in vertebrates, which is located within the body and provides support and protection to internal organs. A hydrostatic skeleton is a structure found in some soft-bodied animals, consisting of fluid-filled cavities that provide support through pressure; this is seen in organisms like jellyfish and earthworms. An articulated skeleton refers to a skeleton that consists of bones or segments that are connected at joints, allowing for movement but does not specify whether it is external or internal, highlighting the functionality rather than the positioning related to the epidermis.