Glaciers have caused extensive erosion in all of these places except:
a.) the appalachian mountains
b.) the northern united states
c.) the cascade mountains
d.) the rocky mountains

A) the Appalachian Mountains

Explanation:

Glaciers have caused extensive erosion in all of these places except for the Appalachian Mountains. Glaciers can have an important impact on the environment due to their great erosive power. Glaciers erode the environment in three major ways: plucking, abrasion and freeze thaw. Although the process is slow, over time glaciers can completely change the scenery of a place.