In which of the following changes of state is mass conserved?

The correct answer is All of the above.

Practical lens: Link apparatus, readings, and uncertainty to the exact measurement named in the objective. This question asks: In which of the following changes of state is mass conserved. The correct response is All of the above, because density links mass and volume, so the answer must preserve which quantity is being calculated. In Changes of state, the marking point should connect directly to explain that mass is conserved when a substance changes state. 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 Changes of state and the particle model, 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 182 is distinct because it uses this exact question context and the practical lens rather than a generic particle-model sentence.