<span>If two metals both have the same color, have similar densities, and are about the same size, but one is shiny and the other is dull, they can be separated based on the lustrous physical property of a metal. Lustrous is the property of the metal to shine/gleam gently because of its particle arrangement of atoms. </span>
Answer: Manholes are usually round, primarily because roundness is the best shape to resist the compression of the earth; covers are round because they are easier to manufacture than square or rectangular shapes, they are easier to move by rolling, and they can't fall into the opening.
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