The number 14 of the process carbon 14 dating denotes
Both kinds of carbon, C-14 and C-12, are absorbed and used by plants and trees during the photosynthesis process and become part of their cellulose structure.
Animals then eat these plants containing carbon-14 and carbon-12 and thus forms of carbon enter their tissues.
(Today, based on refined calculations/techniques the half-life rate of carbon-14 is generally considered to be 5,730 years) (Wheatley 20; De Young 20).
This carbon dioxide includes the stable, common isotope carbon-12 and also tiny amounts of radioactive carbon-14.When plants and animals die, they no longer absorb carbon from the atmosphere and the trace amount of carbon-14 in them starts to slowly decay back to nitrogen (Carbon-14 → Nitrogen-14 Beta (β)).