Skin is made of 3 layers
the top Layer that is exposed to air is the epydermis
the middle layer is the dermis
the lowest and largest layer is the HYPODERMIS. This is the innermost and farthest from the surface of the skin
Ok idk if there was a picture that was supposed to go with that cause I don't see one but here are some vestigial structures in humans: Appendix, Pinky toe (debatable possible used for balance) , ear muscles, tail bone, wisdom teeth, nictitating membrane, male nipples (sorry to be gross), and goosebumps. Those are the ones I can remember. Hope this helps!
Because humans and all other organisms use some combination of these elements. if we lost a whole species everything would be out of balance and we would slowly lose everything and in the in, causing a global scale extinction event. <span />
