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Across
  1. 2. A state of matter with fixed shape and volume.
  2. 3. Found in nature.
  3. 7. Made by humans, not found in nature.
  4. 8. Likely to break down or change.
Down
  1. 1. Elements 57–71 on the periodic table.
  2. 2. Not likely to change or decay.
  3. 4. Mass per unit volume.
  4. 5. A state of matter with no fixed shape or volume.
  5. 6. A state of matter with fixed volume but no fixed shape.