Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

Pathological enlargement of this organ is called Menetrier's disease, and hematemesis can result from persistent bleeding in it. The uppermost portion of this organ is called the fundus, which contains glands whose chief cells secrete zymogens. Another secretion of this organ is necessary for B12 absorption and is called (*) intrinsic factor. Its surface area is increased by folds called rugae. This organ's parietal cells secrete hydrochloric acid, which, along with enzymes like pepsin, works to produce chyme from macerated food. For 10 points, name this organ between the esophagus and the small intestine.

Science