Question

on what does the shape of the stomach depend

Answer 1

size of belly depends the shape of the stomach

Answer 2

The shape of the stomach depends upon how much fat the person has in his body, and sometimes...when we eat a lot, even thin people will get a slightly outward tummy...It also depends on genetics.
Sometimes, when the parents have a thin tummy, even the child will have the same.When the parents are fat, genetically, even the child will be fat, even though he tries to exercise.
So, there are multiple reasons for the dependency of the stomach's shape.

Hope it helps...
^_^