Once an organism dies, it stops taking in carbon-14.
A portion of the carbon is the radioactive isotope carbon-14.
For example, this study shows detectable levels of carbon-14 in a range of carbon-containing materials that are supposedly 1-500 million years old.
Surprisingly, the study includes from several different locations!
Clearly, such huge time periods cannot be fitted into the Bible without compromising what the Bible says about the goodness of God and the origin of sin, death and suffering—the reason Jesus came into the world (See Six Days? He said, This only makes sense with a time-line beginning with the creation week thousands of years ago.
It makes no sense at all if man appeared at the end of billions of years.