| http://www.w3.org/ns/prov#value | - Topics included are: the importance of animals and other organisms to maintaining healthy soil; the ancient practices of farming from around the world, including the irrigation systems of Afghanistan and Pakistan; how deserts, sand dunes, and quicksand are formed, and what types of sand they are made up of; ancient and modern uses of sand and soil from blown glass to mud brick houses; and the meth
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