AFOQT Practice Test

What defines matter?

1. Anything that has energy

2. Anything that has mass and occupies space

3. Only substances that are solid

4. All forms of energy

The correct answer is: Anything that has mass and occupies space

The defining characteristic of matter is that it has mass and occupies space. This means that anything considered matter—whether it is solid, liquid, or gas—has a measurable mass and takes up a certain volume in three-dimensional space. This property distinguishes matter from forms of energy, which do not have mass or occupy space in the same way. The other options do not accurately capture the definition of matter. For instance, stating that anything with energy defines matter is misleading since energy can exist in forms (like light or heat) that do not have mass. Similarly, limiting the definition to only solid substances ignores liquids and gases, both of which are forms of matter. Lastly, describing all forms of energy as matter is incorrect because energy, by definition, does not have mass or volume. Therefore, the correct response encapsulates the complete essence of matter as being both mass-bearing and space-occupying.