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Where does the availability of water pose the greatest problem

The meseta in spain is a a. navigable river b. castle c. coastal plain d.plateau

Which are practical examples of how people in the developed world could make a big difference in how much water they use check all that apply a. use lightbulbs that use less electricity b. consider using a composting toilet that does not use water c. avoid using your telephone during peak hours d. do not read books