One of its protons eventually decays into a neutron and an electron, spitting out the electron. That transforms the carbon-14 back into nitrogen. If carbon-14 weren't continually created, it would disappear. This unstable carbon disperses throughout the environment. Plants photosynthesize it.
Animals breathe it.
Bigger animals eat plants and the smaller animals. Thus carbon-14 works its way into every living organism. In 1947, chemist Willard Libby realized this provided a way to figure out how long something has been dead. That innovation won Libby a Nobel Prize and has enabled archaeologists and paleontologists to date the Dead Sea Scrolls, Egyptian mummies, bones of mammoths and other organic objects up to about 50,000 years old. By then, 99.7 percent of the carbon-14 has decayed away, making accurate dating difficult.