Across
- 4. materials or sources of energy that cannot be easily replaced
- 5. a source of energy made from the remains of ancient, once-living things.
- 7. something that is foun in nature and is valuable to humans.
- 8. electricity produced by water power.
- 9. a type of fuel made from biomass, or living or formerly living material.
Down
- 1. a material that is replaced quickly in nature.
- 2. energy obtained from Earth's interior.
- 3. a source of energy other than burning fossil fuels.
- 6. power obtained from solar energy (aka from the sun)