Crossword Puzzle

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Across
  1. 4. overpopulated variation competition
  2. 6. natural process where something takes place
  3. 7. the natural process which takes place
  4. 9. makes individuals better to adapt
  5. 10. levels can kill
Down
  1. 1. only individuals with a desired trait
  2. 2. 1858
  3. 3. origin of species
  4. 5. the struggle among living things
  5. 8. studied pet and farm animals