Concept:Polarization and local action are separate defects in a primary cell.
Explanation:Hydrogen bubbles collect on the copper plate (cathode) during cell operation.
This accumulation is called polarization.
It increases the internal resistance of the cell.
It also reduces the effective voltage and current output.
The formation of hydrogen bubbles on the electrode is the cause of these effects.
Local action, however, is caused by impurities in the zinc electrode, not by hydrogen bubbles on the copper plate.
Therefore, local action is
not a consequence of hydrogen bubbles covering the copper plate.
Answer:C. local action