Across
- 2. the strength and vitality required for sustained physical or mental activity.
- 3. fuels, like coal or natural gas, that are made of decayed plants and animals
- 6. energy given off by the sun’s rays
Down
- 1. energy produced by natural resources that cannot be used up, such as the wind or sun
- 4. panel designed to absorb the sun's rays as a source of energy for generating electricity or heating
- 5. devices that convert sunlight into electricity