The Nitrogen Cycle

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Across
  1. 2. after death the composition of plants and animals breaks down
  2. 7. extra nitrogen in the soil gets put back into the air - special bacteria perform this task
  3. 9. cycle this describes how nitrogen moves through plants,animals, bacteria, and the atmosphere
  4. 10. process by which ammonium gets changed into nitrates by bacteria, which plants can absorb
  5. 11. about 78% of this is made up of nitrogen
Down
  1. 1. an element that is very important to plants and animals
  2. 3. plants and animals die and decay returning nitrogen back to the soil through decomposers which turn it back into ammonium
  3. 4. plants absorb nitrates from soil through their roots
  4. 5. this helps nitrogen change states so it can be used by plants and animals
  5. 6. this is the first step in the process of making nitrogen usable by plants; bacteria change nitrogen into ammonium
  6. 8. nitrogen is used in this to help plants grow
  7. 10. oxide this is another name for laughing gas