Across
- 1. a layer in the earth's atmosphere
- 3. the study of the relationships between living organisms
- 5. composed of layers with different properties, such as specific gaseous composition, temperature, and pressure
- 6. the natural home or environment of an animal, plant, or other organism
- 7. to protect something
- 10. the surroundings or conditions in which a person or organism lives
Down
- 1. made without chemicals
- 2. restored or replaced by natural processes
- 4. sun energy
- 8. ability to maintain or support a process over time
- 9. the process of collecting and processing materials that would otherwise be thrown away as trash and turning them into new products