Elles crossword

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Across
  1. 1. a deep undersea valley were crust sinks towards the mantel
  2. 5. the process by which crust sinks bake into the mantel at a
  3. 6. bodies of water
  4. 8. ocean rig an undersea chain of mountains that is part of a long
  5. 9. a device that reflects sound waves off under objects and
Down
  1. 2. plat bondery
  2. 3. of underwater mountains
  3. 4. the echoes
  4. 7. floor spreading the process by which molten adds new crust bellow