Final answer:
The reduced form of a substance has more energy than the oxidized form because it gains electrons during a redox reaction, whereas the oxidized form loses electrons and thus loses potential energy.
Step-by-step explanation:
The question is asking about the energy difference between oxidized and reduced forms of a substance. In a redox reaction, the substance that is oxidized loses electrons and has decreased potential energy, while the substance that is reduced gains electrons and has increased potential energy. Therefore, the reduced form of a substance has more energy than its oxidized form. This is because the electrons, which contain potential energy, are transferred to the reduced compound, thus increasing its energy. The oxidizing agent gains electrons and is reduced, and the reducing agent loses electrons and is oxidized. This is analogous to how energy is spent to move rocks uphill, and as they roll down, they release energy. Similarly, when electrons move to a compound with a higher affinity for them, energy is released and can be harnessed for work within the cell.