Which best describes the first law of thermodynamics as compared to the second law of thermodynamics?

The first law of thermodynamics is the conservation of energy: energy, including thermal energy, cannot be created or destroyed, though it can change form or move between objects. It does not tell which direction heat will naturally flow. The second law addresses that direction: heat tends to move from warmer objects to cooler ones. Therefore, the best choice is “The first law describes how thermal energy is conserved but not the direction it moves.”

AI-written and checked against the verified answer.