Your skin protects your internal organs in so many different ways. I will name a few for you! :)
Protects from damage - Your skin protects your internal organs from damage such as cuts and bruising. Our skin is not incredibly strong, but it does make a huge difference compared to our organs being bare.
Protects from bacteria - Your skin blocks most bacteria from directly having contact with your internal organs. Most people get sick because bacteria is let into contact with internal organs through our mouths, noses, etc. Our skin does not let bacteria in.
Keeps internal organs warm - Skin is not fur, it does not provide significant resistance to cold. However, it does make a big difference compared to bare organs. It protects our internal organs from heat by sweating, as well as cold by preventing too much cold from reaching our organs.
I hope this helped. Have a great day!
