Across
- 1. One of the greenhouse gases and a product of photosynthesis
- 4. The scientific word for burning
- 5. the type of combustion that produces carbon monoxide
- 10. the most abundant gas in today's atmosphere
- 11. The gas that plants take in
- 12. this is caused by burning fuels with sulfur impurities
- 13. The first plants
Down
- 2. The gas that plants produced
- 3. Finish the phrase: ______ change is caused by global warming
- 6. One of the three main fossil fuels
- 7. a greenhouse gas produced by cattle
- 8. A planet with the same atmosphere as the early earth
- 9. The structures that produced the early earth's atmosphere