Please choose the correct answer to the 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?

Answer1: Earthquake activity folded the rock layers. Answer2: Volcanic eruptions destroyed a rock layer. Answer3: Erosion removed several layers of rock. Answer4: Weathering changed the layering of the rocks.

Answer format: answer1/answer2/answer3/answer4