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Water and soil are brought into the indus river valley as a result of a. high winds b. annual floods c. long droughts d. seasonal tornadoes

24-karat gold is considered to be pure gold. 18-karat gold is considered to be about 75% gold. what is 18-karat gold considered a mixture rather than a pure substance? a) it has a variable composition of other elements and minerals. b) its color is different than pure gold. c) the gold atoms are not arranged in a repeating pattern. d) it can be melted and transformed into a different substance.

Describe how gravity and convection work together to move the plates in the plate tectonics theory