Plant respiration, sea, organic cbon in soilExplanation:When plants or ppire they take up the carbon dioxide and let out oxygen:6 CO2 + 6 H2O (+energy) -->6 O2 + C6H12O6 In addition phytoplankton absorbs carbon dioxide using the same process as normal plants. In addition, the sea is able tools carbon dioxide. Lastly, soil retains organic carbon from decaying carcasses.