Final answer:
The jejunum connects to the ileum, with the former absorbing most nutrients and the latter absorbing vitamin B12 and bile salts.
Step-by-step explanation:
The jejunum connects to the ileum, which is the third and final part of the small intestine. The jejunum is responsible for the absorption of most of the nutrients from digestion, including sugars, amino acids, and fatty acids, whereas the ileum absorbs vitamin B12, bile salts, and any remaining nutrients not absorbed in the jejunum.
Both parts are key components of the small intestine and contribute to the digestive process, being tethered to the posterior abdominal wall by the mesentery and framed by the large intestine.