Final answer:
The skin functions as both a sensory organ and a protective barrier.
Step-by-step explanation:
The functions of the skin include sensation and protection. The skin has sensory receptors that allow us to perceive touch, temperature, and pain. It acts as a protective barrier, preventing dehydration, infection, and injury to the rest of the body. For example, when we touch something hot, our skin senses the heat and sends a signal to the brain to move our hand away. The skin also helps to regulate body temperature by sweating when the body gets overheated, and by constricting blood vessels when it's cold to help retain heat. Therefore, the correct answer is D. Sensation; protection.