skin
The skin, wrapped in vertebrates of the soft layer, is one of the organs in the body is the largest organ. The skin blocks foreign intrusion and keeps moisture. There is warm, blocking, feeling used. The role of the skin varies from species to species, there is warm, protective color, attract the opposite sex and so on. The skin of each species is thick and thin, thick leather called leather. The skin is part of the epidermis system and is the largest organ system of animals, consisting of multiple layers of ectodermal tissue that protects internal muscles, bones, ligaments and other internal organs. Some species, such as fish and reptiles, will be protected by scales. Birds will make feathers protected. The skin of amphibians is the organ that exchanges gas. All mammals have skin on their hair, even if the seemingly hairless marine mammals are actually hairy. ...