Answer:
Nitrogen is present in the atmosphere in a molecule form about 78 percent. This nitrogen comes to the earth with the water through rainfall. Some nitrogen fix by beneficial microorganisms such as Cyanobacteria and Azotobactor which are present in the roots of higher plants. These microorganisms convert nitrogen molecule into nitrates and used by the plants. There are some other microorganisms which again convert nitrate into nitrogen molecules, called denitrifying bacteria and nitrogen molecule goes to the atmosphere again and complete the cycle.
Theory because a theory is a well substantiated explanation of how a particular phenomenon works based on the set of facts which had been repeatedly confirmed through observations and experiments. A scientific theory gives reliable account of a phenomenon.
This varieation can be justified because since they had different variations they probably had different niches which led them to evolve differently,this will help because the two species will have no competition
Lactobacillus is the answer for this question
