Answer:
this is the SUBMUCOSA
Explanation:
The wall of the digestive tract contains 4 walls in addition to the submucosa
These are the muscularis external ,(the external layers of muscles that contract s and relax for propelling chime and chyle)
the mucosa
, and serous membrane. The mucous gland secrets Mucus for lubrication of the tubule.
the endoscopy is important for diagnosis and endoscopy therapy
it is also useful for identify the dept of tumor and other abnormalities.
