Reversible change means you can change a substance back to the way it was before the change of state happened. Non-Reversible is the other way around. Choose the best alternative for the pictures.
non-reversible, reversible, reversible, non-reversible
reversible, reversible, reversible, non-reversible
reversible, non-reversible, non-reversible, non-reversible
non-reversible, reversible, non-reversible, reversible