Final answer:
Small amounts of absorption can take place in the mouth, particularly substances like alcohol and aspirin, despite most absorption occurring in the small intestine.
Step-by-step explanation:
True, small amounts of absorption can take place in the mouth. While most digestion and absorption occur in the small intestine, some substances like alcohol and aspirin are absorbed directly through the mucous membranes of the mouth. The mouth also initiates the process of chemical digestion, where enzymes begin to break down food molecules.
Most nutrients, however, are absorbed further down in the gastrointestinal tract, particularly in the small intestine, which is highly specialized for this function with its villi. These structures increase the internal surface area, facilitating the absorption of digested food particles into the bloodstream.