Answer:
One method that allows scientists to tell the age of the rocks are radiometric dating; this method is done by finding the natural radioactive decay of elements like carbon; for EX. rocks found deeper in the core of the earth will have less carbon than rocks found shallower in the earths core.
What this method can tell us about the history of earth is that through the collection of the levels of carbon and other properties that were in the air from older rocks, we can tell if an event occured during the earths history that configured those properties in the rock.
Step-by-step explanation: