river water carries sediment from mountains to oceans

rivers dry up, causing lakes to form

which best describes river erosion

River erosion is the process by which water and other erosive forces, such as wind and ice, wear away at the banks and bed of a river, carrying sediment from the mountains to the ocean. This process can cause the river to change its course, form new channels, and create features such as waterfalls, rapids, and gorges.