Concept:The small intestine is the longest segment of the human alimentary canal (digestive tract).
Explanation:The alimentary canal is a continuous tube from the mouth to the anus.
Its main parts include the mouth, oesophagus, stomach, small intestine, large intestine, and rectum.
Among these, the small intestine has the maximum length.
It measures about
6.7 meters, which is roughly
3.5 times the length of the human body.
Although it is called "small" due to its narrower diameter, it is actually the longest part of the digestive tube.
The small intestine is divided into three sections: duodenum, jejunum, and ileum.
It is the primary site for digestion and absorption of nutrients.
In contrast, the stomach is a J-shaped organ about
25–
30 cm long.
The large intestine is about
1.5 meters long and wider than the small intestine.
The rectum is a short terminal part of the large intestine, only about
12–
15 cm long.
Therefore, the small intestine is the longest among the given options.
Answer:Small intestine.
