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Across 4. an autotroph 8. process by which non-photosynthetic convert inorganic chemicals to organic compounds without solar energy 9. the non-living factors of the biosphere 10. feeds on producers 11. the extent to which a surface can reflect light 12. the number of species in an ecosystem 14. a protective layer of the atmosphere which shields us from UV radiation 15. another name for burning 17. when water vapour becomes liquid water 18. organism that feeds on other organisms 21. the removal of soluable minerals by percolation 24. species which no longer exists anywhere 26. top level of the region below ground which is saturated with water 27. feeds on both plants and animals 28. the total dry mass of all the dry material in an ecosystem 29. waste from dead plants and animals

Down 1. feeds on detritus 2. the process by which plants use CO2 solar energy and water to make carbohydrates 3. the process by which nitrates are converted to nitrites 4. the downward pull of water 5. scientific study of energy transformations 6. an organism that synthesizes organic compounds from inorganic compounds without the use of solar energy 7. slowly decomposing plant matter produced in low-oxygen environments such as bogs 13. cultivation of a single species 16. food chains that link between each other 19. a group of the same species living together 20. living factors of biosphere 22. chemicals that are essential to living things 23. a polar molecule 25. number atoms in an oxygen molecule