Let's consider the Flood and use what is called the "canopy theory." There is some evidence for a canopy surrounding the Earth before the Flood.
The canopy would probably not stop all the cosmic rays themselves, but a good deal of the scatter radiation would be reduced. Thus, there would be a few neutrons and fewer C-14 atoms formed.
Some of the scientists who date by C-14 claim these are only small fluctuations and would have no overall effect.
And on the basis of these methods, many scientists announce that the Bible's record of history is not accurate.
But the cosmic ray bombardment changes moment by moment, day by day and week by week.
Such activity as sun spots or solar storms will affect the cosmic radiation.
The plant, animal and human will each have about the same ratio of C-14 to C-12 as does the air.
The next question is: Where did the air get its C-14?