The fossil remains of a terrestrial organism are found in Canada. These fossils appear to be similar to fossils found in the Midwestern United States, and also to fossils found in Northern Europe. What would be the best first step in a scientific procedure for determining if one of these organisms could be an ancestor of the others?

A. Reconstruct the environments that these organisms might have lived in using modern knowledge of climatology.
B. Compare the fossils to modern-day organisms to find any modern organisms that may have evolved from the fossilized organisms.
C. Search for more fossils in other surrounding regions to try to identify how the organisms migrated to the other continents.
D. See if any of the organisms lived before the others by measuring the age of their fossils using some means, like radioactive dating.

Fossils are mostly found in sedimentary rock not igneous rocks. Sedimentary rocks can be used in dating the fossils found in them using radioactive carbon. The age of the fossils must be determined to determine the ancestry of these fossils and their evolution. Dating the rocks and minerals with the use of radioactive isotopes is known as radioactive dating. Geologists make use of radioactive dating in knowing when were the rocks formed and the age of the remains of fossils in the rocks and comparing the result with one another to know whether they could be an ancestor of the other.