Fact 1: Hydrogen bonds cause water to expand when it freezes.

Fact 2: Hydrogen bonds Hydrogen bonds are primarily electrostatic in origin.

Given the two facts above, answer the question "What causes water to expand?" with the following options: 
- evaporation
 - Condensation
 - Generating heat
 - electrostatic
 - friction
 - heat energy
 - heat produced
 - wind and erosion


 

    electrostatic     