Final answer:
The greatest amount of digestion occurs in the duodenum, where most chemical digestion takes place. The jejunum follows and is where most nutrient absorption into the bloodstream occurs.
Step-by-step explanation:
The Greatest Amount of Digestion in the Small Intestine
The greatest amount of digestion of food occurs in the duodenum, which is the first and shortest part of the small intestine. This is where most chemical digestion takes place due to a high concentration of digestive enzymes that break down the complex molecules in food. These enzymes are secreted into the duodenum and work to digest proteins, fats, and carbohydrates. The duodenum receives digestive juices from both the pancreas and the walls of the intestine itself, effectively starting the chemical digestion process.
Following the duodenum is the jejunum, which is the second part of the small intestine. Here, the process of hydrolysis continues, and it is where most of the carbohydrates and amino acids are absorbed into the bloodstream. The bulk of chemical digestion and nutrient absorption occurs in the jejunum, making it a pivotal part of the small intestine for the body's absorption of nutrients.