Across
- 3. What is the thin layer protecting Earth from harmful UV radiation?
- 4. What is the primary source of energy for Earth?
- 6. What is the main component of the atmosphere?
- 7. Which layer of the Earth contains all living organisms?
- 10. What is the term for the variety of life in the world?
Down
- 1. dioxide What gas do humans exhale?
- 2. What is the process by which plants make food using sunlight?
- 5. What is the process of converting waste into reusable material?
- 8. Which renewable energy source uses wind turbines?
- 9. What gas is most responsible for the greenhouse effect?