Brittany wants to use a model to study soil erosion on hills. she is told that farmers can prevent soil erosion by plowing so that their furrows run along hills instead of up or down hills. she fills a pan with dirt, packs the dirt firmly, then shapes it into parallel furrows. what should brittany do with her pan of dirt next in order to study soil erosion? a. prop up one end of it to make a slope and carefully pour water over it b. shake the pan rapidly back and forth c. set it outside and check on it every day d. fill the pan with water, then tilt it until all the water runs out