Answer:
In carbondioxide
Explanation:
During cellular respiration, the glucose is oxidized in the presence of oxygen and produce byproducts in the form of carbon dioxide and water. So when glucose with radioactive carbon is fed to mice then the radioactive carbon in glucose will be found in the carbon dioxide after respiration because the 6 carbon atom in glucose converts into 6 carbon atom of CO2 in the respiration process.
Cellular respiration reaction:
C6H12O6 + 6O → 6CO2 + 6H2O
Therefore we can find radioactive carbon atoms in the carbon dioxide after the mice completely oxidize the glucose in cellular respiration.