Answer:
None of these answers, that I know of, remove carbon dioxide from the air, photosynthesis how ever does in fact do that.
Explanation:
Photosynthesis removes CO2 from the atmosphere and replaces it with O2. Respiration takes O2 from the atmosphere and replaces it with CO2.
The answer is : temperature estimated using any of several methods. The most important variable in reconstructing ancient climate is temperature estimated using any of several methods.
