THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -Digestion begins immediately in the oral cavity with both mechanical and chemical digestion. Mechanical digestion in the oral cavity consists of grinding of food into smaller pieces by the teeth, a process called mastication.

Detailed explanation-2: -Mechanical digestion is a purely physical process that does not change the chemical nature of the food. Instead, it makes the food smaller to increase both surface area and mobility. It includes mastication, or chewing, as well as tongue movements that help break food into smaller bits and mix food with saliva.

Detailed explanation-3: -Mechanical digestion of protein begins in the mouth and continues in the stomach and small intestine. Chemical digestion of protein begins in the stomach and ends in the small intestine.