it came from volcanos maybe? Carbon stored in rocks, melt, carbon dioxide emmisions then broken down to o2 and carbon?
It comes from the air.
The carbon-based life forms that are the plants around us absorb CO2 from the atmosphere, break it up into oxygen and carbon, emit the oxygen back into the atmosphere, but retain the carbon. Plants use the carbon to physically grow and build their very structure-—the same carbon they derive from the CO2 they absorb from atmospheric air.
Look at an oak tree. The carbon in that wood literally came from thin air!
“carbon dioxide emmisions then broken down to o2 and carbon”
__________
I see now you’ve got it of course but many don’t make the connection.
More CO2 in concentration in the atmosphere flat out means a greater volume of vegetative growth, all else being equal. It’s a good thing one would think. But no. We need to see a slow uptick in atmosphetic CO2 concentration from drastic post-ice-age lows as a telltale sign of the inherent earth-damaging nature of the human race.