The main factors that can cause soil erosion and transport particles include:Water (hydraulic action) - flowing water in rivers, streams, rainfall runoffWind - air movement that picks up and carries soil particlesGravity - causing mass movement downslopeIce - glaciers that can transport materialSince the question specifically mentions "as it flow", this is referring to water as the erosion agent. Water flows and carries rock and soil particles from one location to another through:Sheet erosion (thin layers of water flowing over the surface)Rill erosion (small channels)Gully erosion (larger channels)Stream and river flow