Fact 1: Temperature changing can cause phase changes.

Fact 2: Melting is the change of phase from a solid to a liquid.

Given the two facts above, answer the question "What can cause melting?" with the following options: 
- Changing pressure
 - Heat energy
 - Water expanding
 - Evaporation
 - converting electricity to heat
 - Increase in mass
 - Temperature changing
 - Chemical reaction


 

       Temperature changing  