(っ◕‿◕)っ Hey There!
Answer ➜ Skin serves many important functions including:
1. protecting the body from environmental factors such as bacteria, fungus, viruses, allergens, water, and chemicals
2. regulating body temperature by sweating and adjusting blood flow to the skin
3. synthesizing vitamin D
4. helping the body sense touch, pain, temperature, pressure, and position
5. providing some protection against the sun's harmful ultraviolet rays via the skin protein melanin
✧☺ Hope this Helps! ✧☺
Im guessing the answer is a because sometimes the air quality is not good for you to in hale