Miller used ammonia (nh3) as a reactant in his experiment. the atmosphere is 78% nitrogen; however, why would using a nitrogen source be important in this experiment

I think using a nitrogen source would be important in this experiment because nitrogen is found in nucleic acids and proteins. The large amount of nitrogen in the atmosphere would be important in the experiment. Nitrogen element is found in a lot of compounds making it easy to access and that is why there is a lot of it in the atmosphere.