Biogeochemical cycles

6. Animals and plants (can/cannot) directly use all the nitrogen found in our atmosphere
8. Some of the phosphorus in soils can be washed away into ____
15. what is the main regulator of CO2 in the atmosphere
16. Higher organisms use nitrogen to make ____
18. huge deposits of carbon are burned as _____
19. Water from oceans and lakes _____ into the atmosphere
20. Animal waste decay by the action of bacteria which create ______
21. Too much phosphorus in water leads to plant _____
22. Phosphorus is an essential nutrient in life as it makes up chemicals such as ____

1. phosphorus is mostly contained in _____
2. Plants use CO2 in this process to make sugar and oxygen
3. too much CO2 is released in the atmosphere may be responsible for ____
4. another source of CO2
5. ____ in the soil can break down the ammonia into the gaseous form of nitrogen, which is not available for use by plants and animals
7. Animals use oxygen in this process to make more CO2
9. another source of phosphorus in water comes from ____
10. Water falls to the surface as ______
11. The evaporated water _____ to form into clouds
12. Some water seeps into the ground and becomes _____
13. special bacteria that can directly use nitrogen in our atmosphere and “fix” it so other organisms can benefit
14. Groundwater is taken by the plants’ roots through ______
17. our atmosphere is 78% _____