Across
- 2. a fossil fuel found underground that is mostly made up of methane
- 7. a type of coal mining used when the coal is located deep below the Earth's surface
- 9. a type of nonrenewable energy that is not a fossil fuel; the material used in nuclear power plants is nonrenewable
Down
- 1. a process where high-pressure water splits apart underground ricks, releasing trapped natural gas
- 3. the most common source of nonrenewable energy (coal, petroleum, and natural gas)
- 4. oil' a liquid fossil fuel found in underground rock formations
- 5. a type of coal mining used when the coal is located near the Earth's surface
- 6. describing a resource with a limited supply and that takes a long time to regenerate
- 8. a process where the inner core of an atom is split and energy is released