Fact 1: When a cooler object touches a warmer object , thermal conduction occurs.

Fact 2: Thermal conductivity varies with sediment type.

Given the two facts above, answer the question "When a cooler object touches a warmer object, conductivity varies with what?" with the following options: 
- heat energy
 - flow of electrons
 - voltage
 - activation energy
 - Electrical energy
 - sediment type
 - energy barrier
 - friction


 

      sediment type   