Treating water is used to remove harmful substances before drinking, and boiling is the safest method of treating water. Given these facts, what can be done to water to remove harmful substances before drinking among the following options:
- evaporation
 - vaporization
 - Dipping a magnet into it
 - hydration
 - Mixing in heavy metals
 - Cooking
 - Boiling it
 - Adding purified water to it


 

       Boiling it  