Which organ system has the principal function of protection, water retention, thermoregulation, vitamin D synthesis, cutaneous sensation and nonverbal communication?

Answer:THE SKIN

Explanation: The Skin is the largest organ of the body, it is located on the outside of the human body, it carries out several activities aimed at ensuring the well-being of a organisms.

The following are some of the activities of the Skin

Osmoregulation (regulation of the internal environment through osmosis), protection (prevents certain substance from entering the body), Water retention (holds enough water required for moisturizing the body), thermoregulation (manages the internal temperature of the body), Vitamin D synthesis, cutaneous sensation and nonverbal communication etc.