Think of it this way:
DNA inside cells store all the genetic information on a person's looks, eye colour, hair colour etc. It makes them unique. The analogy of being like books in a library basically suggests that in a library there is so much information and every book is different with different knowledge... That's basically what DNA is; millions of different information things.
Applying ice to a fire victim leads to tissue hypoxia and necrosis because it will change the skin's temperature too fast and may cause frostbite. The burn could have had removed a layer of skin, leaving the fragile tissue exposed which will be more sensitive to the ice.
Similar: They are made by proteins and glycoproteins like all the cells are. The also have DNA or RNA to reproduce and they also evolve to adapt.
Difference: They don't use the cell division phase and they are not alive.
