Why is the small intestine the most important organ of the digestive system?

The small intestine serves two important functions of digestion and absorption. In the duodenum, it receives two digestive juices:

1. The bile
2. The pancreatic juice

Both the juices virtually complete the process of digestion of proteins, starch, carbohydrates etc. Once the food is broken down, the small intestine is responsible to absorb simple particles such as amino acids, glucose etc.