THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -Mechanical food digestion in which the food is broken down into smaller chunks increases the surface area for enzyme action and thereby facilitates chemical digestion by breaking down the food by enzymes into simpler nutrients (so that they can be absorbed).

Detailed explanation-2: -Mechanical digestion involves physically breaking down food substances into smaller particles to more efficiently undergo chemical digestion. The role of chemical digestion is to further degrade the molecular structure of the ingested compounds by digestive enzymes into a form that is absorbable into the bloodstream.

Detailed explanation-3: -Villi are the finger-like projections, found in the small intestine which help in increasing the surface area for efficient absorption of nutrients. They contain blood vessels and lacteals.