You are presented with the question "How does water turn to ice?" and the following answer choices: 
- Adding air
 - The bending of a ray of light
 - Warm air moving into cold air
 - Increasing heat energy
 - It used to be covered by water
 - evaporation
 - Adding salt
 - Reducing heat energy

Now knowing that freezing means changing from a liquid into a solid by reducing heat energy and solid ice is melted into liquid water, choose the best answer.


 

        Reducing heat energy 