An example of a physical change during is when teeth are crushing and cutting food into smaller pieces.

The blank should be digestion (process).

The action of cutting food into smaller pieces with teeth is a physical change/digestion, because this action does not involve enzymes, which are necessary for chemical digestion, examples are such as turning starch to Maltose.

The action of cutting and crushing food can increase the surface area, so that it can speed up the chemical digestion later on and provide the most nutrients for the body.