A thematic map is designed to show distribution of human or natural features or data. Example:population
<span>It was called that, but that is wrong. Actually, what is now called the Middle East was where the first Civilizations started. Sumer, Akkadia, and Babylon were the first three and they existed long before the area of Italy was civilized. It is even possible that Greece was civilized earlier than Rome. If you ask a Greek, they will say it is so anyway.
</span>
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.
