B4 revision

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Across
  1. 4. carbon in the atmosphere is constantly ____
  2. 7. a type of plant, with mutualistic properties, whose roots contain nitrogen fixing bacteria
  3. 8. living factors
  4. 9. a relationship where both organisms benefit
  5. 11. the gas that makes up 78% of the atmosphere
  6. 13. process by which plants produce glucose
  7. 16. non living factors
  8. 19. process by which animals and plants release CO2 back into the atmosphere
  9. 20. when life attempts to take the upper hand in a situation
Down
  1. 1. a process that repeats itself, usually in the same manner
  2. 2. all the organisms living in a habitat
  3. 3. a factor that living things compete for
  4. 5. as the number of predators increases the number of prey
  5. 6. turns atmospheric N2 into nitrogen compounds usable by plants
  6. 10. is broken down into ammonia
  7. 12. all the organisms of one species in a habitat
  8. 14. all the living and non living things in an area
  9. 15. a natural process which convert atmospheric N2 into nitrates
  10. 17. an organism that breaks down living matter
  11. 18. a life form that lives off another host life form