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Often on a topographic map, every fifth contour line is darkened. what is this line called? a. key b.slope c.benchmark d. index contour

In the lab, ammonia was mixed with water to form ammonium hydroxide. what is/are the reactant(s)? o water and ammonia o ammonia o ammonium hydroxide need

Which sentence about particles in matter is true? a. atoms are present in solids and liquids but not in gases. b. the particles of matter are in constant motion. c. the same kinds of atoms are found in different elements. d. when a solid changes to a liquid, the sizes of the particles change.