Duodenum is the correct answer.
Most of the small intestine is located in the abdominal cavity. A small amount (approximately the first 10 inches or so) is located behind the abdominal cavity, in what is called the retroperitoneal space. Roughly speaking, the small intestine is framed or bordered by the large intestine. The small intestine is part of the digestive tract and located in the stomach.
duodenum
they are called villi
Villi
ilea
The omentum.
villi
Yes
serosa
The membrane that connects parts of the small intestines is called the mesentery. It provides support and helps anchor the intestines to the abdominal wall, allowing for blood vessels, nerves, and lymphatics to reach the intestines.
small intestines makes the transition to the large intestines here through what is called the ileocecal valve.