Final answer:
The correct location for the absorption of large polypeptides, oligopeptides, and free amino acids is the small intestine, with the involvement of enzymes such as pepsin, trypsin, and chymotrypsin.
Step-by-step explanation:
The absorption of large polypeptides, oligopeptides, and free amino acids primarily takes place in the small intestine. This is a process that begins in the stomach with the action of the enzyme pepsin, which starts the breakdown of proteins into smaller polypeptides. The process continues in the small intestine where pancreatic enzymes like trypsin and chymotrypsin further digest these polypeptides into smaller peptides and free amino acids. Finally, specific carrier systems in the intestinal epithelium actively transport these digested proteins across the cell membrane, allowing them to enter the bloodstream.