"One special kind of mercury-in-glass thermometer, called a maximum thermometer, works by having a constriction in the neck close to the bulb. As the temperature rises, the mercury is pushed up through the constriction by the force of expansion." Its not changing form, so its not A, its not C because change of state is defined as "A change of state occurs whenever matter changes from one state to another. ... They are reversible changes that do not change matter's chemical makeup or chemical properties. Processes involved in changes of state include melting, freezing, sublimation, deposition, condensation, and evaporation." i dont think its chemical change because "Chemical changes occur when a substance combines with another to form a new substance" therefore the answer is D.
