Answer: The correct answer for the blank is - B. endothermic.
A cold pack is used as a first aid chemical to releive conditions like pain, inflammation, and injury.
It draws heat from the surrounding area and thus gives a sensation of coolness on touch.
Endothermic process can be described as a chemical process in which energy (in the form of heat) is absorbed from the surrounding, and stored in the form of new chemical bonds during the process. It cools the surrounding.
Thus, in a cold pack, an endothermic reaction draws heat from the surroundings.
