Which system contains the teeth, saliva, stomach, small intestine, large intestine and colon?​

Digestive system.

Explanation: Assuming that you are human, you use this system a few times a day. They system is one of the bodies key functions to remain alive. The teeth grind down the food, the saliva allows it to be swallowed, the stomach has acids that break down the food, the small intestine absorbs the nutrients from the food eaten, the large intestine gets rid of the waste left over.