Step-by-step explanation:
so we will know a substance has oxidized when it is acting as in reducing agent when a substance is having in its own element when it is being added to another element it is basically being gained so as a result it is being oxidized and when a compound gets broken into substances which is simplar like an element you will know that it is being reduced oxidizing agent is the one which is undergoing the reduction and the reducing agent is the one which is undergoing the oxidation.