Across
- 2. return to a previous state
- 5. the state of the atmosphere
- 7. use me as stair
- 8. an area often covered with sand or rocks
- 9. a large steep hill
- 12. all round a particular place or thing
Down
- 1. placed before a noun to find the relation with other words
- 3. the presence of harmful substance in the air
- 4. no longer useful
- 6. the envelope of gases surrounding the sun
- 10. something of great value
- 11. a habitat