Studying the decay of radioactive isotopes in dead organisms helps scientists to identify fossilized remains. The ratio of C-12 to C-14 in the atmosphere is 1 x 1012. The table shows this ratio inside the body of three organisms. C12/C14 Ratio
Organism C12/C14 Ratio
X 8 x 1012
Y 2 x 1012
Z 1 x 1012

What can most likely be concluded from the above information?
Only Organism Z is alive, and Organism X has been dead longer than Organism Y.
Only Organism Z is alive, and Organism Y has been dead longer than Organism X.
Only Organism X is alive, and Organism Y has been dead longer than Organism Z.
Only Organism X is alive, and Organism Z has been dead longer than Organism Y.