Why are the Rocky Mountains larger than the Appalachian Mountains?

The Appalachian mountains were formed over 480 million years ago. That is at least quadruple the millions of years that it took for the Rockies to form. ... The Appalachians were actually at one time presumed to be as large as or bigger than the Rockies, but time and erosion have whittled them down to where they stand now.

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Explanation:

The Appalachian mountains were formed over 480 million years ago. That is at least quadruple the millions of years that it took for the Rockies to form. ... The Appalachians were actually at one time presumed to be as large as or bigger than the Rockies, but time and erosion have whittled them down to where they stand now.

answer; i believe that one of the correct answers is preventing human development;