Third part of the small intestine.

Third part of the small intestine.

• A. Ileum
• B. Duodenum
• C. Pericardium
• D. Raynaud's disease

Answer: (A)

The small intestine has three parts in order: the first is the duodenum, the second is the jejunum, and the third is the ileum. The ileum is the final section where digestion continues and most nutrient absorption happens, with a key role in reabsorbing bile acids and vitamin B12 as part of enterohepatic circulation. It’s located after the duodenum and jejunum and ends at the ileocecal valve. The other options aren’t parts of the small intestine: the pericardium is the membrane surrounding the heart, and Raynaud's disease is a vascular condition affecting extremities.

The small intestine has three parts in order: the first is the duodenum, the second is the jejunum, and the third is the ileum. The ileum is the final section where digestion continues and most nutrient absorption happens, with a key role in reabsorbing bile acids and vitamin B12 as part of enterohepatic circulation. It’s located after the duodenum and jejunum and ends at the ileocecal valve.

The other options aren’t parts of the small intestine: the pericardium is the membrane surrounding the heart, and Raynaud's disease is a vascular condition affecting extremities.