Since this is not my area of expertise, I searched Google under the key words "Nitrogen fixation" to get these possible sources:
http://en.wikipedia.org/wiki/Nitrogen_fixation
(Broken Link Removed)
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.
Nitrogen fixation is carried out primarily by humans by...
A. Humans.
B. Plants.
C. Bacteria.
D. Consumers.
1 answer
1 answer