In 1949, American chemist Willard Libby, who worked on the development of the atomic bomb, published the first set of radiocarbon dates.
His radiocarbon dating technique is the most important development in absolute dating in archaeology and remains the main tool for dating the past 50,000 years.
Plants are not the only organism that can process Carbon-14 from the air.
The extra neutrons in Carbon-14’s case make it radioactive (thus the term, radiocarbon).
Radiocarbon is produced in the upper atmosphere after Nitrogen-14 isotopes have been impacted by cosmic radiation.
Radiocarbon is then taken in by plants through photosynthesis, and these plants in turn are consumed by all the organisms on the planet.
So every living thing has a certain amount of radiocarbon within them.