2. (4 pts) Thermos is the brand name for a vacuum bottle for insulating a liquid from the ambient air. A basic schematic of a vacuum bottle is shown. If the liquid inside is colder than the air outside, and the black lines shown are solid walls and the gray area shown is the vacuum, identify the dominant mechanism of heat transfer in each of the following regions: Air: Solid wall: Vacuum: vacuum What is the most important physical property of the solid wall in this application