What is the definition of mechanical digestion?

Mechanical digestion refers to the breakdown of food into smaller parts by means of a mechanical process i.e. by physically breaking the food apart into smaller bits. Mechanical digestion begins in the mouth where the teeth chew apart the piece of bread you have just eaten. This has the advantage of increasing the foods surface area which allows enzymes in the stomach to break down the food chemically. Hope this helps! Please message me if you have further questions 😊