Domains of the earth

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Across
  1. 4. - not very steep and smaller than mountains
  2. 5. - huge areas covered with sand
  3. 7. - steep and pointy summit
Down
  1. 1. - form of water found in polar regions
  2. 2. - a type of water body
  3. 3. - table like structure
  4. 6. - fertile soil and leveled land