What is an "Organ System" defined as?

An "Organ System" refers to a group of organs that work together to perform a specific function or set of functions within an organism. Each organ within the system contributes to the overall operation, facilitating complex processes necessary for the maintenance of life. For example, the digestive system includes the mouth, stomach, intestines, and liver, all of which collaborate to process food and absorb nutrients.

The other options do not accurately reflect the definition of an organ system. A single organ, while crucial, does not encompass the collaborative nature of an organ system. A cellular structure refers to the components within a cell, and a basic unit of life pertains to cells as the foundational units of all living organisms, neither of which encompass the combination of multiple organs working together.