Question

The longest part of the alimentary canal is
A. Oesophagus
B. Large Intestine
C. Small Intestine
D. Stomach

Answer 1

The human digestive system is also known as the alimentary canal or the Gastro-intestinal tract. It involves various organs through which the food passes during the process of digestion, and the associated glands.

Complete step by step answer:
Small intestine is the major site at which the process of digestion and absorption of the ingested food particles takes place. Thus it is the longest part of the alimentary canal is the small intestine. The length of the small intestine is 7 meters. It accounts for about three-and half times the total body height. It takes an average of about 4 hours for the food to pass through the small intestine. Even the surface area of this organ is increased, due to the presence of numerous projections known as villi.
Considering the other options:
Oesophagus is also known as the food pipe. This passage through which the food moves from the pharynx to the stomach. The length of this organ is about 25cm which is less than the small intestine. The food moves down the esophagus due to a continuous peristaltic motion.
Large Intestine has a greater diameter than the small intestine, but the length is less than that of the small intestine. The large intestine is only about 1.5 meters long. This is the site of action of the gut flora.
Stomach is the organ in which the process of digestion starts to a large extent. The empty human stomach is only 12 inches long, with 6 inches width. It has various infoldings known as Rugae.
Thus, the most appropriate answer is C.

Note:
The accessory digestive organs, which are present, are pancreas, liver and gallbladder. These organs produce the enzymes and factors, which are involved in digestion. The mouth, tongue, teeth and the salivary glands also function as the part of the digestive system.