B4 revision

1. carbon in the atmosphere is constantly ____
4. all the organisms living in a habitat
7. a life form that lives off another host life form
11. when life attempts to take the upper hand in a situation
12. as the number of predators increases the number of prey
15. a factor that living things compete for
17. a natural process which convert atmospheric N2 into nitrates
18. a type of plant, with mutualistic properties, whose roots contain nitrogen fixing bacteria
19. is broken down into ammonia
20. a process that repeats itself, usually in the same manner

2. all the living and non living things in an area
3. an organism that breaks down living matter
5. process by which plants produce glucose
6. all the organisms of one species in a habitat
8. the gas that makes up 78% of the atmosphere
9. process by which animals and plants release CO2 back into the atmosphere
10. a relationship where both organisms benefit
13. living factors
14. non living factors
16. fixing bacteria, turns atmospheric N2 into nitrogen compounds usable by plants