Answer the following question: Fact 1: Radioactive dating is used to determine the age of fossils. Fact 2: For sedimentary rock, fossils provide the relative age of deposition. Given the two facts above, radioactive dating is used to determine the relative age of what?

Options:
1). discovery;
2). ageless;
3). rocks;
4). blastoids;
5). departation;
6). deposition;
7). sea urchins;
8). bones;
Answer:
6).