• Body concentrates order. It continuously self-repairs. Every five days you get a new stomach lining. You get a new liver every two months. Your skin replaces itself every six weeks. Every year, 98 percent of the atoms of your body are replaced. This non-stop chemical replacement, metabolism, is a sure sign of life.

    Lynn Margulis, Dorion Sagan (1995). “What is Life?”, p.17, Univ of California Press