In the given reaction, Zn (s) + CuSO4 (aq) → ZnSO4 (aq) + Cu (s), zinc (Zn) is oxidized to form Zn2+ ions and copper ions (Cu2+) are reduced to form solid copper (Cu).
Therefore, the oxidizing agent in this reaction is CuSO4 (aq), which causes the oxidation of Zn by accepting electrons from it. The reducing agent, on the other hand, is Zn (s), which causes the reduction of Cu2+ ions to form solid copper (Cu).