Question: Two pieces of the same metal are placed on a table. The pieces of metal have the same density, mass, and texture. Which characteristic must be the ONLY difference between the two samples?

  Options: 
 A. They have different dimensions.
 B. They have different boiling points.
 C. They are made up of a different type of matter.
 D. They contain a different amount of matter per unit volume. 
Answer: A