Boiling is when liquids are heated above their boiling point, and vapor pressure is about liquids boiling. Given these facts, vapor pressure is caused when among the following options:
- liquids expand
 - It gets heated up
 - liquids condense
 - liquids are heated
 - Evaporation
 - Light passing through water
 - Water expanding
 - liquids freeze


 

    liquids are heated     