Where did the original atmospheric oxygen come from

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.

the answer is "d"

(context) if you were to travel to the middle east and go into peoples homes there would be like 4 generations in there

(more context) i'm pretty sure in the middle east they take loyalty and family bonds very serious

(last bit of context) i'm also positive that extended families are most commonly found in urban areas

i believe this is