Which of the following is NOT a function of the skin?

The production of vitamin K is not a function of the skin, making it the correct answer in this context. Vitamin K is primarily produced in the liver and is essential for blood clotting and bone metabolism. While the skin does play a role in the synthesis of certain vitamins, such as vitamin D when exposed to sunlight, it does not produce vitamin K.

In contrast, the other options highlight critical functions of the skin. Temperature regulation is achieved through mechanisms such as sweating and blood flow, helping to maintain the body’s internal temperature despite external changes. Sensation is facilitated by the multitude of nerve endings found in the skin, allowing it to respond to various stimuli, including touch, pressure, pain, and temperature. Additionally, the skin serves as a storage site for energy in the form of fat within the adipose tissue located in the subcutaneous layer, providing insulation and protection.