What methods allow scientists to tell the age of rocks and what does this tell us about the Earth’s history

To establish the age of a rock or a fossil, researchers use some type of clock to determine the date it was formed. Geologists commonly use radiometric dating methods, based on the natural radioactive decay of certain elements such as potassium and carbon, as reliable clocks to date ancient events.

Explanation:

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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.

Explanation:

answer; ///i believe the answer your looking for is (ribosomes);

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.