Across
- 4. Apart from intense heat, what other condition is needed for the formation of oil and gas?
- 5. What is released into the air when fossil fuels are burned?
- 6. What environmental problem is caused by increased greenhouse gases?
- 8. What term describes energy resources that will eventually run out?
- 10. Which fossil fuel produces the most carbon dioxide when burned?
- 11. What is the main element found in fossil fuels that releases energy when burned?
- 12. What renewable energy source comes from the Sun?
Down
- 1. Wind energy converts what energy to electrical energy?
- 2. What term describes the total amount of carbon dioxide a person or activity produces?
- 3. What energy comes from the heat from inside the earth?
- 4. What is the first stage of coal formation?
- 7. What type of fuel is coal, oil, and natural gas classified as?
- 9. What renewable energy source uses plant and animal waste?
- 13. Which fossil fuel is a liquid commonly used to make petrol and diesel?