The following are the differences of human and frog digestive systems:
1. Humans possess stable teeth which they use for chewing while frogs do not possess stable teeth to grip their prey.
2. Chewing for humans is an automatic digestion while frogs do not chew their prey but swallow it instead.
3. Humans possess only a set of teeth while frogs possess two sets of teeth.
4. Human's tongue is inclined behind the mouth while the frog's tongue is inclined to the opening of the mouth.
5. Humans possess a lengthy small intestine while the frog possess a more concise small intestine.
6. The expulsion of undigested food in human is through the rectum while in frog, it is through the cloaca.