Across
- 3. Scientific study of interactions between living organisms and their environment.
- 8. Process that changes liquid water into water vapor.
- 9. Layer of gases surrounding Earth.
- 10. Natural pathways that recycle essential elements through the environment.
- 14. Process where water vapor forms clouds.
- 15. Non-living components of an ecosystem.
- 16. Water falling from clouds to Earth.
- 17. Solid outer layer of Earth.
- 18. Process where plants convert carbon dioxide into food.
- 19. Excessive growth of algae caused by nutrient enrichment.
- 23. All the water found on Earth.
- 27. The first step of the scientific method.
- 30. Process of converting nitrogen gas into ammonia.
Down
- 1. The ability to do work.
- 2. Sphere where all living organisms exist.
- 4. Gas released by plants during photosynthesis.
- 5. Process that converts nitrates back into nitrogen gas.
- 6. Rain made acidic by sulfur dioxide.
- 7. Living components of an ecosystem.
- 11. Law stating that energy cannot be created or destroyed, only transformed.
- 12. Organized body of knowledge gained through observation and experimentation.
- 13. Gas that makes up about 78% of Earth's atmosphere.
- 20. A testable explanation for an observation.
- 21. Common name for a harmful algal bloom.
- 22. Process where plants release water vapor into the atmosphere.
- 24. Separation of waste into different categories.
- 25. The second most abundant element in organisms by mass.
- 26. Founder of modern ecology.
- 28. Practice of converting waste into useful materials.
- 29. Study of relationships between organisms and their environment.