Which type of digestion involves the physical breakdown of food?

Mechanical digestion refers to the physical process of breaking down food into smaller pieces, making it easier for enzymes to further break down the food chemically. This type of digestion includes actions such as chewing in the mouth, mixing food with saliva, and the churning of food in the stomach. These processes do not alter the chemical structure of the food, but they help increase the surface area for enzymes to act upon during chemical digestion.

In contrast, chemical digestion involves the biochemical breakdown of complex molecules into simpler molecules through enzymatic actions, while ingestion is simply the process of taking in food. Absorption pertains to the uptake of the nutrients from the digestive tract into the bloodstream. Thus, mechanical digestion is specifically associated with the physical alteration of food.