Answer:
Epithelial tissues.
Step-by-step explanation:
The digestive system is made up of organs and as you have outlined here, the Stomach, pancreas and Intestine are all organs of digestion.
But the tissues line the walls of these organs. The stomach processes The mucous membrane of the stomach contains simple columnar epithelium tissue with many exocrine cells. Small pores called gastric pits contain many exocrine cells that secrete digestive enzymes and hydrochloric acid into the lumen, or hollow region, of the stomach
The pancreas have flattened cuboidal epithelium that extends up into the lumen of the acinus to form what are called centroacinar cells.
The mucosa of the small intestine is lined by a simple columnar epithelium which consists primarily of absorptive cells (enterocytes), with scattered goblet cells and occasional enteroendocrine cells. In crypts, the epithelium also includes Paneth cells and stem cell