<span>Nitrogen fixation
This process creates organic compounds, including ammonium, that contribute to the growth of a plant in much the way fertilizer does. Many plants have evolved to facilitate nitrogen fixing bacteria in their roots as to promote production of these organic compounds when the soil quality is poor or lacking in these bacteria.</span>
It's letter c i believe, because they need the DNA's instruction on how to copy the exact tissue copy.
The answer is B) These fuels are available in a limited supply- - when the fuel is used it is no longer available.
