The United States has been consuming iron ore at the rate of R(t) million metric tons per year at time t, where t is measured in years since 1980 (that is, t=0corresponds to the year 1980)

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igneous rocks also form where plates converge. the subducting plate melts as it sinks into the crust of the earth, and the melt rises into the overriding plate forming volcanoes. metamorphic rocks are formed mainly in the lithosphere, wherever there is high pressure and high temperature. -woods

answercollision;