What evidence would scientist use to determine the age of rock in a layer?

Question

Index fossils
Living fossils
Resin fossils
Trace fossils

Answer 1

Scientists would use index fossils to determine the age of rock in a layer. Index fossils are fossils that are known to have existed during a specific time period and can be used as markers to determine the age of the rock layer in which they are found. By identifying index fossils in a rock layer, scientists can establish the relative age of that layer compared to other layers containing similar index fossils.

Answer 2

So what is the correct answer?

Answer 3

Index fossils