The digestive system
The system has lots of organs but not everyone has all there organs like your gallbladder and part of your liver. The digestive system is important because you can not digest all the food.
The mouth is the start of the process. The mouth chews the food into little molecules. Because example you can not swallow a whole piece of bread without it being small enough to enter the esophagus that's why the mouth what the mouth dose and the saliva helps break down the food. The tongue pushes the food down to the esophagus.
The esophagus is a long twisty tube that connects the stomach to the mouth. Thats a motion called peristalsis is a rhythm that squeezes the food the takes six seconds to the stomach
The stomach is a squishy bag that churns the food to fit into the small intestines. Also the stomach is not as big as the small intestine.
The small intestine is 7 meters if you stretch it out but if you don't it is just a sausage like tube. That brakes down down the fat and it sent to the large intestines.
The large intestines squeezes the juice out of the food to be turned into faeces which is pushed out by the anus.
So remember the digestive system is always important . because it produces nutrients.