Fact 1: Melting means changing from a solid into a liquid by adding heat energy.

Fact 2: All temperatures are measures of heat energy.

Given the two facts above, answer the question "what is increased to cause something to change from a solid into a liquid?" with the following options: 
- Evaporation
 - water vapor
 - hydrogen
 - temperature
 - ice cubes
 - h2o
 - sweating
 - Water expanding


 

    temperature     