According to the Second Law of Thermodynamics, what happens during energy transfer?

The Second Law of Thermodynamics states that during energy transfers, the total entropy of an isolated system always increases over time. Entropy is a measure of the randomness or disorder of a system, and as energy is transformed or transferred, some of it becomes unavailable to do work. This leads to an increase in disorder, meaning that in any energy exchange, the overall entropy of the universe tends to rise.

This principle explains why no energy conversion process is 100% efficient; energy often dissipates as heat, increasing the entropy of the surroundings. Therefore, the correct answer highlights the inevitability of increased entropy in energy exchanges, a fundamental concept in thermodynamics that describes the natural progression of energy transformations in the universe.