Answer:
Explanation:
Your description corresponds to the picture attached.
In that model, the spheres represent atoms or molecules (is the same) of a substace. You can call them particles.
The particles tightly packed inside the cylinder of the left represent a substance in solid state whose particles are in a fix position and cannot move freely.
The particles randomly distributed throughout the cylinder on the right model a substance is gas state, where the particles occupy the whole space, moving freely.
Thus, the image depicts the change of a substance from solid state to gaseus phase. Such change is defined as sublimation.
Therefor, the answer is the third choice of your list: sublimation.
