The most likely explanation for this phenomena is that this is a result of natural selection.
What actually happened?
When the insecticide was introduced, it killed all of the organisms that were vulnerable to it. However, there was a portion of the population that was immune. Since the immune individuals were the only ones that have survived and left offspring, after some generations in the population of this organism there were only their descendants that have the resistance to the insecticide.
Answer:
C.
Explanation:
Nitrogen fixation is a process by which molecular nitrogen in the air is converted into ammonia or related nitrogenous compounds in soil. Atmospheric nitrogen is molecular dinitrogen, a relatively nonreactive molecule that is metabolically useless to all but a few microorganisms.
