ENVIRONMENTAL SCIENCE

1. ^ The nonliving components of an ecosystem.
7. FIXATION ^ The process of converting atmospheric nitrogen into ammonia.
9. ^ The ability to do work or transfer heat.
11. ^ The part of Earth where living organisms exist.
13. ^ The process in which water vapor changes into liquid.
16. ^ Water that falls from clouds as rain, snow, sleet, or hail.
18. CYCLES ^ Natural pathways through which essential elements are recycled.
21. ^ The process of removing salt from seawater.
22. METHOD ^ The process used to investigate scientific questions.
23. ^ Excessive growth of algae caused by nutrient pollution.
24. ^ A testable explanation for an observation.
25. ^ The most abundant gas in Earth's atmosphere.
26. ^ The process by which plants convert sunlight into food.
28. ^ Water stored beneath Earth's surface.
29. ^ An essential element found in ATP, DNA, and bones.

1. SCIENCE ^ The branch of environmental science that studies Earth's atmosphere.
2. ^ The study of the geographic distribution of organisms.
3. ^ The scientist who proposed the Four Laws of Ecology.
4. ECOLOGY ^ The branch of ecology that studies energy flow and nutrient cycling.
5. CYCLES ^ The natural recycling of matter through living and nonliving components.
6. ^ Organized body of knowledge obtained through observation and experimentation.
8. ^ The living components of an ecosystem.
10. ^ The process in which bacteria convert nitrates into nitrogen gas.
12. ^ The study of interactions between organisms and their environment.
14. ^ Earth's outer solid layer.
15. RAIN ^ Rain made acidic by sulfur dioxide and nitrogen oxides.
17. ^ The process by which plants release water vapor.
19. ^ Everything that affects an organism during its lifetime.
20. ^ The protective blanket of gases surrounding Earth.
27. DIOXIDE ^ The greenhouse gas released by respiration and fossil fuel combustion.