Across
- 4. : Essential gas for human respiration
- 5. : Branch of science dealing with matter and energy
- 7. : Tool engineers use to measure length precisely
Down
- 1. : Study of living organisms
- 2. : Opposite of “synthetic”; naturally made
- 3. : Source of renewable energy from moving air
- 5. : Waste material that can harm nature
- 6. : Device that converts sunlight into electricity
- 8. : Machines that can perform tasks automatically