GEOLOGY

Detailed explanation-1: -In relative dating, scientists do not determine the exact age of a fossil or rock. They look at a sequence of rocks to try to decipher when an event occurred relative to the other events represented in that sequence. The history of a section of rocks can be deciphered using the principles outlined in this concept.

Detailed explanation-2: -Cross dating is a method of using fossils to determine the relative age of a rock. Fossil remains have been found in rocks of all ages with the simplest of organisms being found in the oldest of rocks. The more basic the organism the older the rock is.

Detailed explanation-3: -The relative age of a rock is its age in comparison with other rocks. If you know the relative ages of two rock layers, you know which is older and which is younger, but you do not know how old the layers are in years.

Detailed explanation-4: -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.