Final answer:
Relative dating is a system for determining the age of artifacts by comparing rock layers and index fossils.
Step-by-step explanation:
Relative dating is a system for determining the age of artifacts by comparing rock layers and index fossils. It is based on the principle that older rocks and fossils are found in lower layers of sedimentary rock, while younger rocks and fossils are found in higher layers. This method does not provide an absolute age in years, but it allows scientists to determine the relative order of events in Earth's history. For example, if a fossil is found in a layer of rock that is below another layer containing a different fossil, the fossil in the lower layer is older than the one in the higher layer.