Across
- 4. Carbon dioxide is a substance made of a carbon atom and two __________ atoms.
- 6. When burned, these provide energy and release carbon dioxide into the atmosphere.
- 8. A large farm where animals are kept
- 10. The gas produces when humans breathe.
- 12. When fossil fuels are burned, carbon is released into the __________.
- 13. Animals breathe using a process called __________.
Down
- 1. A type of fossil fuels
- 2. Able to be maintained over time because methods used do not hurt the environment.
- 3. This element is found in all living things.
- 5. The type of environment (biome) where cattle graze.
- 7. The process in which plants make their own food.
- 9. oil and natural gas are examples.
- 11. Cows produce large amounts of this gas as they digest food.