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1. The sun, water, and the wind are other   sources of energy. The wind turns windmills and moves  . It is a clean source of energy, and there is lots of it. Unfortunately, if the   does not blow, there is no wind energy. When   moves from a high place to a lower place, it makes energy. This energy is used to create electricity. Water   gives energy without pollution. However, people have to build dams to use this energy. And as dams cost a lot of money, water energy is  .