Final answer:
Radiometric dating is a method used to determine the absolute age of rocks and fossils by measuring the amount of radioactive materials that have decayed.
Step-by-step explanation:
Radiometric dating is a method used by geologists to determine the absolute age of rocks and fossils. It relies on measuring the amount of radioactive materials that have decayed in each rock layer. By knowing the rate of decay for a radioactive isotope, geologists can estimate the age of a specimen within a range of possible error.