The natural force responsible for shaping the rounded peaks of the Appalachian Mountains is Erosion.

Erosion, caused by wind, water, and ice, has significantly worn down the once-tall peaks of the Appalachian Mountains over millions of years. This process has resulted in the rounded, rolling hills characteristic of the region today. While tectonic uplift initially formed the mountains, erosion is the primary force that has shaped their current appearance, leading to the gentle slopes and valleys seen throughout the Appalachian range.