Most chemical digestion and absorption of nutrients takes place in the _small intestine_.
All macronutrient (protein, carbohydrate, fat) breakdown into their basic subunits (monomers) is finalized in the small intestine. This is where all foodstuffs will meet the last set of enzymes and emolients/emulsifiers (dissolvers) to do the final breaking of bonds (chemical digestion). And it is therefore also in the small intestine that a vast blood supply allows a special circulatory route to absorb (pick up) these nutrients (sugars, amino acids, small fatty acids) via their tiny capillaries, and transport them to the liver for processing. This circuit is known as the Portal Venous System.
