Question

which is the first step that geologists must do to compare rock layers at distant locations?
○ find the absolute age of rocks at both locations
○ compare a layer at one location to layers at other locations
○ identify index fossils in one or more layers at one location
○ collect fossils from different locations to study the organisms’ lifestyles

Explanation:

To compare rock layers at distant locations, geologists first need index fossils (fossils that existed for a short time, widespread) as a reference. Identifying index fossils at one location is the first step because index fossils help correlate rock layers. Finding absolute age is more advanced, comparing layers directly without index fossils is hard, and collecting fossils for lifestyle study is not for layer comparison. So the correct option is the one about identifying index fossils in one or more layers at one location.

Answer:

C. identify index fossils in one or more layers at one location