Identify and describe the two main methods for measuring the age of Earth: Radiation Measurement.
Stratigraphic Superposition.
Explain how scientists use the law of superposition and index fossils to determine the relative age of an unknown item:
Scientists read the rock layers knowing that each layer is deposited on top of other layers. The law of superposition states that each rock layer is older than the one above it. So, the relative age of the rock or fossil in the rock or fossil in the rock is older if it is farther down in the rock layers.
