Fact 1: Freezing causes a solid to form.

Fact 2: When water molecules inside the cell freeze, they occupy a larger space.

Given the two facts above, answer the question "When water molecules expand, what do they begin to form?" with the following options: 
- milk
 - vapor
 - gas
 - solid
 - calcite
 - matter
 - rocks
 - lipids


 

    solid     