Across
- 4. Place where elements are stored in a cycle
- 10. Part of Earth where life exists
- 12. Essential element found in cysteine
- 13. Second most abundant element in living organisms
- 18. Corrosive rain caused by sulfur dioxide
- 20. A testable explanation for an observation
- 22. Measure of disorder in a system
- 24. Conversion of nitrates into nitrogen gas
- 25. Study of weather and the atmosphere
- 27. Makes up about 78 percent of Earth's atmosphere
- 28. Natural process of converting biodegradable waste into fertilizer
- 29. Protective blanket of gases surrounding Earth
- 30. First step in the scientific method
Down
- 1. Living and nonliving components interacting together
- 2. All water found on Earth
- 3. Organized body of knowledge obtained through study and experimentation
- 5. Process that converts carbon dioxide into organic carbon
- 6. Study of interactions between organisms and their environment
- 7. Water stored beneath Earth's surface
- 8. Group of the same species living in one area
- 9. All organisms living in one area
- 11. Excessive algal growth caused by nutrient pollution
- 14. Founder of the Four Laws of Ecology
- 15. Process where liquid water becomes water vapor
- 16. Biologically important inorganic form of phosphorus
- 17. Everything that affects an organism during its lifetime
- 19. Movement of water through plants
- 21. Study of species distribution
- 23. Widely accepted explanation of natural phenomena
- 26. Outer solid layer of Earth