Final answer:
Radiocarbon dating can be used to determine the relative amount of 14C in old grain vs. new grain, but the specific ratio for 2007 AD cannot be determined without additional information.
Step-by-step explanation:
The relative amount of 14C in the old grain vs. the new grain in 2007 AD (At/Ao)2007 AD can be determined using radiocarbon dating. Radiocarbon dating is based on the principle that living organisms absorb carbon-14 from the atmosphere, and once they die, the amount of carbon-14 begins to decrease through radioactive decay. By comparing the amount of carbon-14 in the old grain (At) with the amount of carbon-14 in the new grain (Ao), we can calculate their ratio.
However, the information provided does not include the values of At and Ao, which are necessary to calculate the specific ratio for 2007 AD. Therefore, we cannot determine the relative amount of 14C in the old grain vs. the new grain in 2007 AD without additional information.