About three billion years ago, single-celled organisms called cyanobacteria lived in earth’s oceans. they thrived on the ocean’s abundance of , which they used during the process of photosynthesis. much later, this process allowed organisms, such as fish, to survive by extracting dissolved from ocean waters.
oxygen
carbon dioxide
nitrogen
both blanks need to be filled.
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About three billion years ago, single-celled organisms called cyanobacteria lived in earth’s oceans....
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