Manny designs an experiment to learn about erosion. First, he sets up three long trays with equal-sized piles of sand at one of each tray. Then he sets up Tray A so that it lays flat on a table. He elevates the end of Tray B that holds the sand by 5 cm. Next, he elevates the end of Tray C that holds the sand in each tray. Finally, he observes and measures how far sand is carried by the way water poured into each tray.