Scientists are studying a moving glacier. To monitor the flow of the glacier, they place a series of five markers, A, B, C, D, and E, in a straight line across the path of flow. A and E are closest to the edges of the glacier. C is in the center of the glacier. B and D are between A and C and C and E respectively. How would the scientists predict the motion of each of the markers relative to the edges of the valley down which the glacier flows? What pattern would they predict in the markers over time?