Across
- 5. when plants absorb nitrates or animals eat plants to get nitrogen
- 6. when bacteria and lightning turn nitrogen into ammonia
- 9. the rocky part of the Earth
- 10. plants pull carbon dioxide to make food
- 11. a mixture of gases that surrounds a planet
Down
- 1. fungi and bacteria break down waste and decaying remains
- 2. burning wood, fossil fuels, or organic matter releases stored carbon
- 3. plants and animals break down food for energy and release carbon dioxide.
- 4. composed of all living things
- 7. bacteria turn ammonia into nitrates
- 8. the portion of the Earth that is water