What defines a liquid state of matter?

The correct choice identifies the characteristics of a liquid state of matter accurately. In a liquid state, the molecules are closely packed together but still have some freedom to move around. This arrangement allows liquids to have a definite volume, meaning they occupy a specific amount of space. However, they do not have a definite shape; instead, they take the shape of the container they are in. This is unlike solids, which maintain a fixed shape, and gases, which have neither a fixed shape nor a fixed volume.

This understanding is foundational in HVAC refrigeration, where recognizing the properties of different states of matter is essential for understanding how refrigerants behave during phase changes in refrigeration cycles.