Across
- 1. Main source of energy on the earth's surface
- 4. First organ of digestive system
- 6. Energy used to operate electric heater
- 8. Liquid renewable resource
Down
- 2. First organ of respiratory system
- 3. Gaseous renewable resource
- 5. Wasted energy when using mobile phone for a long time
- 6. is the ability to do work
- 7. Energy stored in the battery