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.
An archipelago...........
Answer:
Cities grew as they became sites of industrial production, centers for banking and other financial networks, the intersections of continental trade routes, and access points for global empires. Other European cities experienced similar or even more rapid periods of growth.
Answer: The Himalayan Mountains are at a convergence plate boundary between the Eurasian plate and the Indian plate.
Brainliest please
Uruguay is the smallest Spanish speaking country in South America.
