Final answer:
Among the options given, the Haversian canals are the structures of the skeletal system that are innervated, meaning they have a supply of nerve fibers.
Step-by-step explanation:
The question asks which structure of the skeletal system is innervated. Innervated means that a part of the body has a supply of nerves or is connected to the nervous system. Among the provided options A. Hair, B. Nails, C. Cartilage, D. Osteoclasts, and E. Haversian canals, it is the Haversian canals that are innervated. The Haversian canals, also known as central canals, are found in the osteons of compact bone tissue and they contain blood vessels, nerve fibers, and lymphatic vessels. These canals allow the bones to be responsive to pain and other sensory stimuli, which is a characteristic of being innervated.