- For an isolated system, no heat or work is exchanged with the surroundings, so the change in internal energy \( \Delta U = 0 \), and \( q = 0 \).
- For a closed system, the system exchanges energy with the surroundings in the form of heat, but the total energy change is still zero, so \( \Delta U = 0 \), but \( q \neq 0 \) due to the heat transfer.
Thus, both statements are correct.