Nutrient cycle

2. A bacteria in soil that can break down the ammonia into the gaseous form of nitrogen
7. What is the special bacteria that can directly use nitrogen in our atmosphere and fix
8. More CO2 is released in the atmosphere today than in the past hour because of what
10. What is the process when Animals use oxygen to make more CO2
13. The animals use phosphorus, and their
15. Plants use CO2 in the process called what
18. Animals and plants cannot directly use all the nitrogen found in our what
19. Our atmosphere is 78%
20. Today these deposits are burned as fossil fuels which include?

1. What do humans use to help grow plants
3. Too much CO2 in the atmosphere may be responsible for the what?
4. Some of the phosphorus in soils can be washed away into what
5. In another part of the cycle, animals eat?
6. Phosphorus is not found in the free state in nature, but is contained mostly in?
9. Animals waste decays by the action of bacteria which creates?
11. Another natural source for CO2 is
12. Higher organisms use nitrogen to make their what
14. Another source of the phosphorus in water comes from man-made what
16. The what is the main regulator of CO2 in the atmosphere
17. Too much phosphorus in water leads to what