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Skin Substitute
A man stands silhouetted behind 21 square feet (2 square meters) of skin substitute, the amount of skin jacketing an average human adult. Engineered from cow-tendon collagen, shark cartilage, and silicone, this skin substitute, Integra, helps surgeons close burn wounds until new skin grows in.
Photograph by Sarah Leen

Skin

See pictures of skin in this photo gallery and from National Geographic.