Which of the following is defined as any substance that occupies space and has weight?

• A. Matter
• B. Energy
• C. Mass
• D. Density

Answer: (A)

Matter is defined as anything that has mass and takes up space. That description fits a substance you can see and weigh, because weight is the gravitational force on mass, so something that occupies space and has weight is matter. Energy, on the other hand, does not have mass and doesn’t occupy space in the same way, so it isn’t matter. Mass is a property of matter, not a substance in itself, and density describes how much mass is in a given volume rather than what the substance is. So the statement points to matter as the correct concept.