Fact 1: When metal conducts heat , that metal expands.

Fact 2: Metals have large specific heats, that is why they conduct heat well.

Given the two facts above, answer the question "Why can metals expand?" with the following options: 
- tectonic plates being pushed together
 - they are shiny
 - flow of electrons
 - matter vibrating
 - they have large specific heats
 - they are hard
 - they can rust
 - electron transport


 

     they have large specific heats    