Freezing means changing from a liquid into a solid by reducing heat energy, and ice is a cold frozen liquid. Given these facts, how is ice made among the following options:
- The area was once underwater
 - Melting it
 - Drying it out
 - salt and water.
 - It gets heated up
 - It used to be covered by water
 - Boiling the water
 - Reducing heat energy


 

        Reducing heat energy 