Final answer:
In a galvanic cell, the action that occurs at an electrode is electron transfer.
Step-by-step explanation:
In a galvanic cell, the action that occurs at an electrode is electron transfer. The electrode in the left half-cell is called the anode and oxidation occurs here. The electrode in the right half-cell is called the cathode and reduction occurs here. Electrons flow from the anode to the cathode, creating a current in the external circuit.