Question

a geologist wants to study how life in an area has changed over time. which technique should the geologist use? comparing the thickness of different rock layers counting how many layers of rock are present analyzing the color and composition of rocks in the area comparing fossils in different layers of rock

Explanation:

To study how life in an area changed over time, fossils are key as they represent past organisms. Comparing fossils in different rock layers (which are deposited over time) shows the evolution or change of life forms. Thickness of rock layers, number of layers, or rock color/composition don't directly relate to life's change over time.

Answer:

comparing fossils in different layers of rock