Final answer:
In the given reaction, Fe is being oxidized and O2 is being reduced. Therefore, Fe is the reducing agent and O2 is the oxidizing agent.
Step-by-step explanation:
In the given reaction, 4 Fe (s) + 3 O2 (g) → 2 Fe2O3 (s), Fe is being oxidized from 0 to +3, while oxygen is being reduced from 0 to -2. Therefore, Fe is the reducing agent and O2 is the oxidizing agent.