Fact 1: Increasing heat causes thermal expansion.

Fact 2: Thermal burns are caused by exposure to heat.

Given the two facts above, answer the question "what can cause burns?" with the following options: 
- epidermis and dermis
 - Pesticides
 - Males and females
 - rays or beams
 - fossil fuels
 - Electrical energy
 - thermal expansion
 - harmful substances


 

       thermal expansion  