Clothing (also known as clothes, apparel, and attire) are items worn on the body. Typically, clothing is made of fabrics or textiles, but over time it has included garments made from animal skin and other thin sheets of materials and natural products found in the environment, put together. The wearing of clothing is mostly restricted to human beings and is a feature of all human societies. The amount and type of clothing worn depends on gender, body type, social factors, and geographic considerations. Garments cover the body, footwear covers the feet, gloves cover the hands, while hats and headgear cover the head. Eyewear and jewelry are not generally considered items of clothing, but play an important role in fashion and clothing as costume. Other wearables are not always considered to be clothing despite belonging to an accepted class, such as orthodontic headgear, which is a medical appliance. The human body is not always complete, and sometimes includes prosthetic devices, such as a limb prosthesis, which might be adorned similarly to an intact body, differently, or not at all. Some styles of prosthetic legs are designed to require ordinary street shoes to function properly. Clothing serves many purposes: it can serve as protection from the elements, rough surfaces, sharp stones, rash-causing plants, insect bites, splinters, thorns and prickles by providing a barrier between the skin and the environment.