Question

during which changes of state do atoms that cannot move past one another become free to move?
vaporization and sublimation
boiling and deposition
sublimation and melting
condensation and melting

Explanation:

In solids, atoms are in fixed positions and cannot move past one - another. Melting is the change from solid to liquid where atoms gain more freedom to move. Sublimation is the change from solid directly to gas, also allowing atoms to move freely. Vaporization (including boiling) is liquid - to - gas, but it starts from a state where atoms can already move past each other (liquid). Condensation is gas - to - liquid and deposition is gas - to - solid, which are opposite processes of making atoms less free to move.

Answer:

C. sublimation and melting