Fact 1: Athermal insulator slows the transfer of heat.

Fact 2: Heat transfer fluids, such as antifreeze, protect the solar collector from freezing in cold weather.

Given the two facts above, answer the question "What protects things from freezing in cold weather?" with the following options: 
- exoskeleton
 - thermal insulators
 - thick filling
 - a hydraulic system
 - Animal fur
 - layers of skin
 - layers of fat
 - deep water


 

  thermal insulators       