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

Ascientist observes certain changes in the physical features of a particular species over time. she concludes that the species has undergone evolutionary change. she wants to study the animals by analyzing their population. she’ll use . the population of this species is decreasing considerably. if this trend doesn’t change, this species will fall under the category of animals. this is a plato question,i need to make up his biology credit.