The following question refers to the following information. Rafael lives near a road at the bottom of a hill. His parents are concerned that soil will wash off the hill and rocks will fall onto the road. Rafael conducts an investigation to find out if grass growing on a hillside will help stop soil erosion. He collects two samples of the same size and type of soil. One sample of soil has grass growing on it and the other does not. He places each sample of soil in a small tray. After pouring the water onto both pieces of soil, Rafael makes an observation. The water collected in the tray under the soil with grass looks clearer than the water collected in the tray under the soil without grass. What conclusion can Rafael make from his observation?
The grass helped to hold the soil in place. The grass helped to move the water through the soil. The soil without grass was sticky, so more water stayed in the soil. The soil without grass was loose, so more water stayed in the soil.