When she eats the sandwich it enters the mouth. When you began to chew, chemical digestion in the mouth can began. I the mouth you break down the food. Now the sandwich can enter the esophagus.
That was a really good sandwich!!
She has ate the sandwich and it is now going down the esophagus which leads the food into the stomach.
Now that the sandwich is in the stomach mechanical and chemical digestive can began. The food can move from the stomach after mechanical digestion is complete. After that the food is now a liquid.
Now that the sandwich is in the small intestine this is were chemical digestion can began. All proteins are broken down in there. The liver, gallbladder, and pancreas all help with this process. The villi is in the small intestine and helps absorbs nutrients.
Now the sandwich has passed into the large intestine. In the large intestine water is absorbed into the bloodstream. There is bacteria in the large intestine that feed on the material.
The sandwich has passed throw the large intestine and now into the rectum. In the rectum the waste is turned into a solid. From the rectum the sandwich gets passed into the anus were the food is digested out the body.