When the ambient temperature drops, the thinnest muscle fibers that make up the skin reflexively contract, which leads to increased energy production, and outwardly manifests itself in raising the hairs on the skin, which form an additional heat-insulating air layer. In humans, this physiological function is expressed to a much lesser extent than in animals.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.