Across
- 5. These are built by humans and beavers that change the flow of rivers and streams
- 7. materials found in nature used by living things
- 9. a man-made lake on the Colorado river that changed the ecosystem
Down
- 1. These can destroy the tops of mountains and cause landslides
- 2. When humans or nature make the water unsafe to drink
- 3. When humans or nature make the air dirty and unsafe to breathe
- 4. Doing this after a forest fire can create new habitats for animals
- 6. caused by humans and nature that can destroy habitats and kill living things
- 8. When animals and plants survive changes to their environments