Explanation

The breakdown of two molecules of glucose in aerobic respiration will produce 12 molecules of carbon dioxide (CO2). 

The balanced chemical equation for aerobic respiration shows that one molecule of glucose (C6H12O6) produces six molecules of carbon dioxide (6CO2).

Therefore, if two molecules of glucose are broken down, the total number of CO2 molecules produced will be:

2 molecules of glucose * 6 molecules of CO2 per glucose = 12 molecules of CO2.