What is the effect of heating a substance on its internal energy?

The correct answer is It increases the internal energy..

Unit lens: Check the units before giving the final statement so the physics quantity is not swapped. This question asks: What is the effect of heating a substance on its internal energy. The correct response is It increases the internal energy., because changes of state are explained by particle energy and arrangement. In Internal energy, the marking point should connect directly to explain why energy transfer can change state without changing temperature. If the question includes values, the working must keep the appropriate unit and operation; if it is an explanation, it must name the relevant particle behaviour or energy change. This item belongs to Internal energy and energy transfers, so avoid answers that switch to a different quantity, confuse heat with temperature, or describe gas pressure without collisions when collisions are the reason. Checkpoint 253 is distinct because it uses this exact question context and the unit lens rather than a generic particle-model sentence.