Which calendar do scientists use to outline the history of life on Earth?

• A. Relative dating
• B. Absolute dating
• C. Geological Time Scale
• D. Evidence

Answer: (C)

The Geological Time Scale is the calendar scientists use to outline the history of life on Earth. It organizes Earth’s long past into units like eons, eras, periods, and epochs based on major changes in life and in the rock record. This framework reflects when key evolutionary events occurred, such as the rise of multicellular life, the age of dinosaurs, and the development of mammals, and it’s built from evidence found in fossils and rock layers. While radiometric dating can give numerical ages for some boundaries, the time scale itself provides the structure for describing when different life forms existed and how they changed over deep time. Relative dating notes which events came first, and absolute dating provides approximate years, but the Geological Time Scale combines both ideas into a coherent calendar for Earth’s history.