Why is the stomach such a muscular organ? How is the stomach lining adapted to its function?
The stomach is muscular organ because it needs to carry all the food that enters in and to stretch to hold the food.
The stomach is lined with mucus to protect the stomach from it's own digestive juices such as Pepsin( digests protein) and Gastric Acid( hydrochloric acid) digests anything. The mucus prevents the acid from destroying the stomach itself.