how do waterfalls form?\na meander gets cut off.\nsediment builds up.\nsoft rock erodes.\nflat areas flood.

Answer

Answer:

C. Soft rock erodes.

Brief Explanation:

Waterfalls form when flowing water erodes soft rock layers more quickly than hard rock layers above them, causing the water to drop over the edge of the remaining hard - rock layer. A meander getting cut off forms an oxbow lake. Sediment building up is related to deposition processes like deltas. Flat areas flooding is not directly related to waterfall formation.