What techniques do scientists use to determine the age of rocks?

Scientists determine the age of rocks using a combination of relative dating and radiometric dating techniques, making this the correct choice. Relative dating methods involve placing rocks and geological events in chronological order based on their position in the geological record, such as using the principles of superposition, cross-cutting relationships, and fossil succession. These methods allow scientists to understand the sequence of events in Earth's history but do not provide specific numerical ages.

In contrast, radiometric dating methods involve measuring the decay of radioactive isotopes within the minerals of rocks. This technique provides precise age estimates, allowing scientists to determine how long ago a rock was formed. By combining these methods, researchers can build a comprehensive understanding of both the relative sequence of geological events and the absolute ages of rocks.

The inclusion of both relative and radiometric dating in dating techniques provides a more complete and accurate picture of geological time, which is crucial for understanding the Earth's history, the evolution of life, and the processes that have shaped the planet over millions of years.