When something gains energy, what can be inferred?

When something gains energy, it means that energy is being transferred or transformed from one system to another due to the conservation of energy principle. This principle states that energy cannot be created or destroyed; it can only change forms or be transferred between objects.

If one object gains energy, it necessarily implies that energy must come from somewhere else, which would result in another object or system losing an equivalent amount of energy. This exchange maintains the overall balance of energy in the system. Therefore, the inference that something else must have lost energy is directly aligned with these fundamental principles of physics.

In this context, the other choices do not align with the conservation principle. For example, the idea that "nothing else changes" contradicts the principle of energy transfer, while suggesting that "energy is created from nothing" directly opposes the law of conservation of energy. Thus, when one entity gains energy, it reflects a broader system of energy exchange among multiple objects or forms of energy.