Final answer:
The state of matter with the lowest density is gas.
Step-by-step explanation:
The state of matter with the lowest density is gas. Gases are composed of molecules that are spaced far apart and have a lot of empty space between them. This leads to their lower density compared to solids and liquids. For example, helium gas has a lower density than water, which is a liquid, and iron, which is a solid.
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