Final answer:
Geologists use relative and radiometric dating to support the geologic time scale. Relative dating helps establish the sequence of events, while radiometric dating provides the exact numerical age of rocks or fossils.
Step-by-step explanation:
Geologists use two methods for dating events in Earth's history: relative dating and absolute dating. Relative dating involves determining the sequence of events and the comparative age of two objects or events. It doesn't establish exact ages but helps establish the order of events. Absolute dating, on the other hand, uses radioactive isotopes to determine the numerical age of rocks or minerals. This method provides an exact age for a particular rock or fossil.