Answer is: Digesting a cracker in the stomach.
Digesting a cracker in the stomach is chemical change (chemical reaction), because new substances are formed , the atoms are rearranged and the reaction is followed by an energy change.
Other examples in this question are physical change, because state of matter and shape are changed.
Physical property can be observed and measured without any changes in molecular composition.
The same substance is present before and after the psysical change, just with different form or state of matter. Â
