Across
- 2. determined by the sun
- 4. to leave dangerous waste everywhere
- 7. without the use of artificial chemicals
- 9. able to fly
- 10. conditions of atmosphere
Down
- 1. used as fuel
- 2. atmospheric pollutants
- 3. not harming the environment
- 5. use again
- 6. important source of oxygen
- 8. the colour of this topic