Why do you think there there are places that stay near an average height all the times?

Places that maintain a near-average height consistently, such as plateaus or flat plains, are typically shaped by geological processes like erosion and sedimentation. These areas often experience a balance between uplifting forces, such as tectonic activity, and eroding forces, such as wind and water. Additionally, climate can influence vegetation and soil stability, helping to sustain a uniform landscape. Consequently, these geological and climatic factors create environments where elevation remains relatively constant over time.