Which process removes carbon dioxide from the atmosphere a: respiration b: humans breathing c: carbonate formation d: nitrogen fixation

The answer is C:  Carbonate formation.  Carbonate formation is the process of removing carbon dioxide from the atmosphere and changing it to carbon-based solids, such as those found in coral skeletons.

Respiration and human breathing both remove oxygen from the atmosphere and add carbon dioxide.  Nitrogen fixation changes nitrogen gas into nitrogenous compounds such as ammonia.