Final answer:
D) duodenum is not one of the major tissue layers of the alimentary canal, which consists of the mucosa, submucosa, muscularis, and serosa. The duodenum is instead a part of the small intestine.
Step-by-step explanation:
The alimentary canal is composed of four basic tissue layers throughout its length. These layers are the mucosa, submucosa, muscularis (or muscularis externa), and serosa. The duodenum is not a tissue layer; it is actually part of the small intestine.
Submucosa
The submucosa lies beneath the mucosa and is a dense layer of connective tissue that includes blood and lymphatic vessels, as well as a network of nerves known as the submucosal plexus.
Muscularis
The muscularis, composed of circular and longitudinal muscle layers, is responsible for the movement of food along the canal and is modified in different sections of the digestive tract to suit specific functions.
The serosa is the outermost layer present in sections of the alimentary canal within the abdominal cavity and is continuous with the mesentery. Meanwhile, the adventitia, a dense sheath of collagen fibers, is found in the mouth, pharynx, and esophagus.