Across
- 2. settle on top of dead organisms
- 3. oil sands and oil shale may be used as sources of ______
- 5. Chemical compounds that are derived from oil and used to make products
- 6. gas tha produces a great deal of energy and is less polluting than other fossil fuels
- 8. An icelike solid that consists of molecules of methane within a crystal network of water molecules
- 10. found within porous rocks deep underground
- 11. in the future, ________hydrate from the deep ocean floor could be used for energy.
- 12. In 1300's, Native Americans of the __________ used colal to heat home, cook food, and fire pottery.
- 13. Is removed from the ground by stripmining or subsurface mining
Down
- 1. The practice of digging shafts deep into the ground to find and remove a mineral
- 4. The deposits of moist sand and clay containing bitumen
- 7. The extraction of a mineral by removing a strip of the layers of soil and rock on top of the mineral deposit
- 9. A rock filled with a mixture of hydrocarbons; can be burned