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Across 1. A layer of gases surrounding the Earth held by gravity. 3. A sequence of organisms that serves as a source of nutrients or energy for the next level of organisms 5. Ecologists assign each organism in an ecosystem to a feeding level 9. The layer of gases containing the ozone layer and acts as a "global sunscreen." 10. water that seeps deeper through soil 11. also called the water cycle 13. Feed on primary consumers 18. Plants make the food they need from compounds in the soil, carbon dioxide, water, and sunlight 22. Organisms that cannot produce their own food 23. consumers that get their nutrients by breaking down nonliving organic matter like dead leaves 24. Consists of Earth's core, mantle, and thin outer crust. 25. a complex network of interconnected food chains 26. primary consumers are also known as ___________________.

Down 2. feed on both primary and secondary consumers 4. Fermentation is also known as _________________. 6. The cyclic movement of phosphorus through water, Earth's crust, and living organisms 7. This cycle involves creating nitrogen compounds by lightning or specialized bacteria in topsoil 8. Net primary ________________ 12. feed mostly on other animals 14. different compounds of carbon circulate through the biosphere, atmosphere, geosphere, and hydrosphere 15. Solar energy is absorbed after reflection off the Earth's surface, providing a warmer layer of atmosphere near the Earth's surface. 16. The layers of atmosphere, hydrosphere, and geosphere where life exists. 17. Gross ____________ productivity 19. eat both plants and animals 20. Includes all the gaseous, liquid, and solid water on or near Earth's surface. 21. Organisms such as plants that make the food they need by photosynthesis