Earth Day Crossword

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Across
  1. 1. To collect and treat used objects to produce new materials
  2. 4. The blue planet
  3. 6. Fuels made from decomposing plants and animals
  4. 7. A tall, strong plant
Down
  1. 2. To protect from loss and damage
  2. 3. A resource that replenishes easily
  3. 5. The introduction of harmful materials into the environment