Rafael Ives near a road at the bottom of a hl. His parents are concerned that soll will wash off the hill and rocks will fall onto the road. Rafael conducts an investigation to find out if grass growing on a hiiside 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. For his investigation, Rafael
pours the same amount of water onto both samples of soil. He uses a large tray to collect water that may flow through the soil.
Which practice shows the best way for Rafael to set up this investigation?