Skim the following paragraph and decide the function of each sentence. 1The market for tourism in remote areas is booming as never before. 2Countries all across the world are actively promoting their "wilderness" regions, such as mountains, Arctic lands, deserts, small islands and wetlands, to high-spending tourists. 3The attraction of these areas is obvious: by definition, wilderness tourism requires little or no initial investment. 4But that does not mean that there is no cost. 5As the 1992 United Nations Conference on Environment and Development recognized, these regions are fragile not just in terms of their ecology, but also in terms of the culture of their inhabitants. 6The three most significant types of fragile environment in these respects, and also in terms of the proportion of the Earth's surface they cover, are deserts, mountains and Arctic areas.