Question: In studying layers of rock sediment, a geologist found an area where older rock was layered on top of younger rock. Which best explains how this occurred?

  Options: 
 A. Earthquake activity folded the rock layers.
 B. Volcanic eruptions destroyed a rock layer.
 C. Erosion removed several layers of rock.
 D. Weathering changed the layering of the rocks. 
Answer: A