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.
Q: Its upper portion forms the top part of the greater curvature. The lesser curvature, which also begins at the cardiac orifice, is about four times shorter than the greater curvature, so it is described as J-shaped. Its volume increases when the rugae are stretched. Parietal cells produce intrinsic factor, necessary for vitamin B12 absorption, and a chemical that activates the zymogen secreted by chief cells. Gelatinase, amylase lipase and pepsin participate in breaking down boli, producing chyme which passes through the pyloric sphincter into the duodenum. FTP, name this organ that lies between the esophagus and small intestine.
A:
Science