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

Comparing rock layers in distant places can be a challenge for geologists since these layers may have different environmental factors that caused different transformations in them.

Therefore, when it is necessary to establish a comparison between layers of rocks in different ligands, geologists must establish steps to make an efficient comparison and have results consistent with reality. To do this, they must first compare a layer in one location with layers in other locations, assign relative age to a layer in one location, and identify index fossils in one or more layers in one location.

14,16 18 reacts with group

it is thermal conduction according to apex : )