B. 13. The food that you eat travels from your mouth, down your esophagus, into your stomach, and through your small and large intestines before your body rids itself of solid waste. As the food passes through your body, it is digested, and you get important nutrients from the food. Which of the following is the term used to describe a group of body parts working together to perform a specific function? OU A. an organism B. a tissue C. an organ system D. an organ​