Class A Fires consist of ordinary combustibles such as wood, paper, trash or anything else that leaves an ash. Water works best to extinguish a Class A fire. Class B Fires are fueled by flammable or combustible liquids, which include oil, gasoline, and other similar materials.
The amygdala is involved in our experience of emotion and in tying emotional meaning to our memories. The hypothalamus regulates a number of homeostatic processes, including the regulation of body temperature, appetite, and blood pressure.
Pleasure and pain are inevitably related on the sled, just as they are in the memories. When, at the end of the novel, Jonas finds a real sled, it symbolizes his entry into a world where color, sensation, and emotion exist in reality, not just in memory.