Where extensive deportation has occurred what is often a result is it increased diversity increase erosion mountain building or improved water quality
When extensive deportation has occurred, the result is typically increased diversity. This happens because deportation typically involves the removal of people from a specific area or country, leading to a change in the demographic makeup of that place. As a result, new groups of people may move in or existing communities may expand their presence, leading to an increase in diversity.
The other options mentioned, such as increased erosion, mountain building, or improved water quality, are not directly related to deportation and are unlikely outcomes of such actions.