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1. What is the main source of energy for life on Earth?

2. Which gas makes up the largest portion of air?

3. What percentage of air is made up of oxygen?

4. What is the term for moving air?

5. What is the process of collecting and storing rainwater called?

6. Which of the following is NOT a renewable resource?

7. What is the major component of fossil fuels?

8. Which of the following helps prevent soil erosion?

9. Wind energy is mainly used for:

10. What is the percentage of nitrogen in the air?

11. The energy from the Sun can be used directly for:

12. What do solar panels do?

13. Which of the following is a fossil fuel?

14. What percentage of the Earth's surface is covered with water?

15. Which is an example of a non-renewable resource?

16. What is one way to reduce the use of fossil fuels?

17. What does the term "fossil fuel" refer to?

18. How do forests contribute to the prevention of soil erosion?