Carbon fourteen dating
Carbon-12 is a stable isotope; that is, it doesn't decay naturally.
Scientists have tried to minimize the uncertainties by using other dating techniques like dendrochronology (tree-ring dating) but their success is questionable and carbon-14 dating remains a controversial dating technique. Jesus, the creator and eternal Son of God, who lived a sinless life, loves us so much that He died for our sins, taking the punishment that we deserve, was buried, and rose from the dead according to the Bible.
Hence, gradually, the ratio of stable carbon to radioactive carbon also decreases.