What process involves biting, chewing, and churning food?

Mechanical digestion refers specifically to the physical process of breaking down food into smaller pieces through actions such as biting, chewing, and churning. This process is crucial as it increases the surface area of food, making it easier for digestive enzymes to access and break down the nutrients contained within.

Biting and chewing, primarily facilitated by the teeth, physically fragment food, while churning occurs in the stomach, where muscular contractions mix and further break down the food. This preparation of food is essential for efficient digestion and nutrient absorption later in the digestive process.

In contrast, chemical digestion involves the breakdown of food through enzymatic reactions that transform food into absorbable nutrients. Absorption is the process where the nutrients from digested food are taken up into the bloodstream. Secretion involves the release of digestive enzymes and other substances that aid in the digestion process. Each of those processes is integral to nutrition, but they serve different functions compared to the purely physical actions classified under mechanical digestion.