What powers the process of evaporation, buy which salt water is turned into freshwater

How did the growth of the middle class affect social reform during the industrial revolution?

George h.w. bush a) hosted the dayton peace talks b) lost support when he agreed to new taxes c) was president when the soviet union collapsed d) ordered relief aid to rwandan refugees

Why would the free rider problem prevent a private business from investing in the building of a city sidewalk?