Across
- 4. of or relating to the sun
- 5. objects strewn or scattered about
- 7. a form of oxygen that is blurry, stinky, used for cleaning supplies, and is renewable
- 10. to keep alive or in existence
- 12. the branch of biology dealing with the relations and interactions between organisms and their environment, including other organisms
- 13. to use or manage natural resources wisely
- 14. a system, or group of interconnected elements, formed by the interaction of a community of organisms with their environment
- 17. capable of being supported or upheld, as by having its weight borne from below
- 19. that has ended or died out
Down
- 1. to treat or process used or waste materials so as to make suitable for reuse
- 2. to make foul or unclean, especially with harmful chemical or waste products
- 3. the gaseous envelope surrounding the Earth
- 6. a low area of land that is built up from deposits of solid refuse in layers covered by soil
- 8. the aggregate of surrounding things, conditions, or influences
- 9. something that is discharged
- 11. nothing of a class of chemical compounds that formerly comprised only those existing in or derived from plants or animals, but that now includes all other compounds of carbon
- 15. a mixture of various decaying organic substances, as dead leaves or manure, used for fertilizing soil
- 16. the natural environment of an organism
- 18. to process used goods or waste material so as to produce something that is often better than the original