Mechanical digestion refers to the physical break down of food particles by the teeth. This process involves grinding, breaking, masticating and tearing of food substances with the teeth. This is done in order to make the food substances smaller for chemical digestion.
The chemical digestion further breaks the smaller food particles into absorbable particles. This is carried out by some enzymes found in the saliva. These enzymes are secreted in the digestive tract and it then breaks the chemical bond holding food particles together.
Therefore, mechanical digestion is done by the teeth while chemical digestion is done by the saliva.
The answer to your question would be, “to show that despite its differences, America is still a country that unites in times of strife.” Hope this helps!:)
