What physical properties of matter can affect density?

The density of a substance is primarily influenced by its mass and volume. Factors such as temperature and pressure can alter density, as heating a substance generally decreases its density by increasing its volume, while increasing pressure can increase density by compressing the substance. Additionally, the phase of matter (solid, liquid, gas) affects density, with solids typically being denser than liquids, which are denser than gases. The composition and structure of a material also play a crucial role in determining its density.