landscapes and land forms

123456789
Across
  1. 4. covers 71% of the earth
  2. 5. produces oxygen, to help breath
  3. 6. the biggest and coldest desert
  4. 8. great plains, these plains began over a billion years ago
  5. 9. the world's most populated island with over 130 million people
Down
  1. 1. formed by tectonic plates
  2. 2. a landform that is situated between mountains
  3. 3. the study of the word
  4. 7. forests, 10,000 millimeters of water per year