Dierdra began writing a summary of the relationship between the first and second laws of thermodynamics.Thermal energy in a system is conserved and can increase the system’s internal energy and/or be used to do work.

The first law says energy is conserved: energy transferred into or out of a system can change its internal energy or do work. The second law describes the natural direction of heat transfer: thermal energy moves from warmer objects to cooler objects. It is not created or destroyed, so choice B completes the summary.

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