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 can change form or transfer between objects, but the total amount is conserved. It does not say which direction heat will naturally flow; the second law explains that heat flows spontaneously from hotter objects to colder ones. Therefore, choice A, “The first law describes how thermal energy is conserved but not the direction it moves,” is correct.

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