Answer:
The purpose of a map scale is to help the user to know the distance between 2 or more cities or geographical elements.
Personally I would say it's A (apart from the installation costs which may make it a little expensive) but it does involve certain aspects of D also as wind energy doesn't cause pollution. So either A or D!
Hope I was of help! :)
As I said in your other post/question on the same topic, you have to rephrase your question in order for us to help you. =)
Two human activities that increase the rate of erosion include farming and deforestation. Both make the top cover of the soil loose making it very easy for it to be carried away by agents of erosion such as wind and water. On the other hand, two natural events that can lead to increased <span>erosion rate include floods and earthquake.</span>
