The correct answer is - cyanobacteria.
The atmospheric oxygen came from the cyanobacteria. These were one of the earliest living organisms on Earth. The cyanobacteria was using photosynthesis in order to create its own food. The photosynthesis process requires sunlight, carbon dioxide, water, and oxygen. The oxygen is mostly released as a waste product from the process of photosynthesis, thus the cyanobacteria were literally releasing oxygen that was ending up into the atmosphere. As more and more cyanobacteria there were across the planet, more and more oxygen they were releasing into the atmosphere, slowly changing the composition of the atmosphere, and setting the basis of it as we know it now.
(-3, -2) I believe it should be
Of these choices i'd say that the third option or "domestic fuels are always cheaper to acquire and renewable". I hope this helps :)
It tells you that there used to be an ocean in the area the rock was found.
