Which of these structures is found in the stomach but nowhere else in the alimentary canal?

A. an oblique muscle layer

B. a lining of columnar epithelium

C. a circular muscle layer

D. mucus-forming cells

A. an oblique muscle layer

Explanation:

The alimentary canal has four main layers:

Mucosa (innermost layer which surrounds the lumen), submucosa (connective tissue with blood vessels, lymphatics, and nerves), muscular layer, serosa (outermost layer of connective tissue).

Muscular layer is subdivided into:

• the inner - arranged in circular rings, prevents food from travelling backward

• outer layer - arranged longitudinally, shortens the tract.

The stomach has an extra layer called inner oblique muscular layer (churning function).