For more on this subject, see the video Bones in Stones i. Ogden III, "Annals of the New York Academy of Science," 288 (1977): 167-173.
As you can probably imagine, researching online how best to handle duck (as in the food) is a more elaborate task than researching how best to store, say, celery. The tough meat of mature ducks is used only in processed products.
Carbon-14 comes from nitrogen and is independent of the carbon-12 reservoir.
If even a small percentage of the limestone deposits were still in the form of living marine organisms at the time of the Flood, then the small amount of carbon-14 would have mixed with a much larger carbon-12 reservoir, thus resulting in a drastically reduced ratio.
This assumption is backed by numerous scientific studies and is relatively sound.
However, conditions may have been different in the past and could have influenced the rate of decay or formation of radioactive elements.
It's assumed that the clock was set to zero when the study material was formed.
This requires that only the parent isotope be initially present or that the amount of daughter isotope present at the beginning is known so that it can be subtracted.
Some scientists argue that the magnetic field of the earth has declined over time.
c) Atmospheric carbon forms just 0.0005% of the current carbon reservoir—99.66% of the earth's carbon exists in limestone, 0.31% in oil and gas, and 0.02% in coal.
Specimens would then look much older than they actually are.
d) Even if the rate of decay is constant, without knowledge of the exact ratio of carbon-12 to carbon-14in the initial sample, the dating technique is subject to question.
A further example from a lava flow off the coast of Hawaii shows similar discrepancies.