Which idea associated with relative dating helped inspire Charles Darwin's work on evolution?

The idea that the earth is extremely ancient.

Explanation:

Charles Darwin was a British naturalist who worked on the organic evolution of living organisms and in his books outlined how present-day organisms evolved from earlier, different species.

Evolution is an extremely slow process. It is difficult to obtain direct evidence of evolution in action. However, scientist including Charles Darwin, have from many fields gathered a great deal of indirect evidence that supports the theory of evolution. This evidence comes from many sources which include the FOSSIL RECORDS.

The history of life on earth is recorded in fossils (remains of organisms preserved mainly in earth's sedimentary rocks). Scientist can determine the age of rocks in which fossils occurs by using RELATIVE DATING. This method give a geological time scale, showing earth's age ( as measured by dating it's rocks), and tracing the history of life on it.

Therefore the idea that the earth is extremely ancient is associated with relative dating which has helped inspire Charles Darwin's work as an evidence on evolution.