Answer:
The answer is D "Particles are farther apart in gases, so substance X is water vapor. "
Step-by-step explanation:
This is because when the particles are separated, they are apart from each other, so it takes up more space than a liquid because in a liquid state the particles are closer together. Think of ice, for example, let's say you fill a cup with 100g of ice and a cup with 100g of water, the ice will take up more space than the water because the particles are separated father than the liquid.