Which of these might be part of an animal's skeletal system?
hair an endoskeleton or exoskeleton the liver and kidneys
An animal's skeletal system provides a strong frame for its body. The skeletal system has three main jobs. First, it supports the animal's body. Second, it protects the organs and other soft parts inside the animal's body. Third, it works with the muscular system to help the animal move.
Some animals have an endoskeleton. The word endoskeleton means "inside skeleton." An endoskeleton is inside an animal's body. Many vertebrates have an endoskeleton. A vertebrate's endoskeleton is made up of bones and fibers called tendons and ligaments. Tendons connect muscles to bones, and ligaments connect bones to other bones.
Some animals have an exoskeleton. The word exoskeleton means "outside skeleton." An exoskeleton is made up of tough structures covering the outside of an animal's body. Many invertebrates have an exoskeleton. Stiff fibers attach the animal's muscles to its exoskeleton.