Answer: C) Age of fossils in the layers of rock.
Step-by-step explanation:
Radioactive dating, also known as radiometric dating, is a technique used by scientists to determine the age of fossils and other materials based on the decay rate of radioactive isotopes. By measuring the ratio of parent isotopes to daughter isotopes, scientists can calculate how long ago the material was formed. This is particularly useful in studying fossils, as it allows scientists to determine the age of the fossils and the geological time period in which they existed. Therefore, radioactive dating is an important tool in helping scientists to understand the history of life on Earth.