What are the similarities and differences of a plain and a valley?

Similarities between a plain and a valley include both being landforms characterized by relatively flat terrain. However, a plain is typically low-lying and lacks significant variations in elevation, while a valley is a depression between hills or mountains with distinct sides or slopes. Valleys are often formed by the action of rivers or glaciers, while plains can be formed by a variety of processes, such as sediment deposition or tectonic activity.