Final answer:
Over time, matter and energy in a system naturally change through various processes. Both matter and energy are conserved, meaning that they are neither created nor destroyed, but are transformed from one form to another.
Step-by-step explanation:
Over time, matter and energy in a system naturally change through various processes. Both matter and energy are conserved, meaning that they are neither created nor destroyed, but are transformed from one form to another. In living systems, molecules combine and separate, matter is rearranged, and energy is redistributed. These transformations maintain the conservation of matter and energy. The laws of thermodynamics govern these changes, with the first law stating that the total amount of energy in the universe is constant, and the second law stating that energy transfers involve some loss of energy in an unusable form.