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.
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The correct answer is B. A watershed is the area contributing water to the runoff of a stream system.
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A watershed or hydrographic basin is a territory drained by a single natural drainage system, that is, its waters give the sea through a single river or that it pours its waters to a single endorheic lake. A hydrographic basin is delimited by the line of the summits, also called water division. The use of natural resources is regulated administratively by separating the territory by river basins, and with a view to the future the river basins are emerging as one of the functional division units with much more coherence, allowing true social and territorial integration through water.
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In 2003 the Federal Republic of Yugoslavia was renamed to State Union of Serbia and Montenegro. The union peacefully broke up when Serbia and Montenegro became independent states in 2006, while Kosovo proclaimed its independence from Serbia in 2008.
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Answer: what does this say haha
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