Across
- 4. fuels that are made from living things like corn or sugarcane
- 5. resources that nature cannot replace after they are used
- 6. heat that comes from the inside of Earth's core
- 7. resources that nature can replace when they are used
Down
- 1. energy that comes from the movement of flowing water
- 2. anything useful or necessary for living beings that occurs naturally on Earth
- 3. is the contamination of air, water, or soil by materials that are harmful to living things