A grasp of psychology is also important in designing a good game; you want to know how players will feel at every point in the game. And it is vitally important that you can explain rules clearly in plain English.
The stomach's main function is digestion. It does this by: The stomach uses pepsin (enzyme) and peptidase (another enzyme) to break down proteins in your food. The acid released by the stomach doesn't break down food it only provides a good environment for the enzymes to work in.
Stomach carries out the physical and chemical digestion of food. When the muscles contract and relax periodically, food is physically digested. The other stomach function, i.e. the chemical digestion of food, is aided by enzymes secreted by glands found in the walls of stomach.