Across
- 1. - human fuel
- 4. - practice this to save energy
- 6. - nuclear energy is released when this is split
- 7. - fuel for cars
Down
- 1. - coal, natural gas, and oil are called ________ fuels
- 2. - when water boils, this is released to do work for us
- 3. - energy from the sun
- 5. - Sun, wind, wood and water are all forms of ___________energy