They are called ISOTOPES.
:)
Answer:
By heating the solution a saturated solution can be changed into an unsaturated solution. Without adding any solvent it can be changed into an unsaturated solution. Example: on heating a saturated solution of sugar in high temperature, it starts dissolving.
The gold leaf (not foil) is to give a sculpture or a painting appeal. Without it, it would discolour quicker.The gold leaf can be easily removed if needed to be.