Given what we know, we can confirm that the three pathways of photosynthesis (C3, C4, and CAM) are all similar in that they use CO2 as the substrate in order to produce sugar, which is carbon-based.
Therefore, we can confirm that each of the three pathways of photosynthesis are similar in terms of carbon and the formation of carbon-based molecules in that each of them uses the Calvin cycle in order to turn carbon dioxide into sugars.
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