In the frog's mouth there is a front hinged tongue. This flips food into the gullet, which is the entrance to the esophagus. The food is moved down into the stomach by muscle contraction. The stomach breaks food down mechanically using its multiple muscle layers. It also secretes enzymes to convert complex nutrients into simpler ones. The enzymatic breakdown continues in the small intestine where the simpler nutrients are also then absorbed. The left over material is passed on to the large intestine where water may be absorbed from the mixture.