Answer:
Yes/no depending on the type of cell
Step-by-step explanation:
In aerobic cellular respiration, CO2 is always of the by-products no matter the cell type as shown by the equation:
The by-product in anaerobic respiration depends on the cell type. In animal cells, lactic acid is the only product. The acid gradually builds up in the cell and create an oxygen debt within the cell because the acid needs to be oxidized to CO2 and water later.
In yeast and plant cells however, CO2 is one of the end products of anaerobic respiration:
Hence, CO2 can be a by-product for both aerobic and anaerobic respiration but this largely depends on the cell type.