Chandler’s science class went on a field trip to walk on a trail by a mountain where they could see layers of rock that were different colors and different thickness. He remarked how easy it was to see which layers of rock were older than the others just by looking at their position. Chandler’s teacher responded that it can be hard to be sure that superposition is the appropriate way to date the layers of rock. Why did his teacher question the use of simple superposition to date the rock layers? (SC.7.E.6.4)