Across
- 5. the relationship between living things and their environment
- 7. expansion of deserts
- 8. atmosphere we live in
- 10. the accumulation of substances
- 11. hazardous substances in the environment
- 12. rise of temperature
- 13. something that no longer exists
Down
- 1. natural occurring process
- 2. downgrading of land
- 3. environment where animals and plants live
- 4. fuels formed from living organisms
- 6. inability to meet basic needs
- 9. the variety of life forms