Two organs are considered part of the same body system if they work together to perform a common function or set of related functions.

Here's a breakdown:

* Body System: A group of organs that work together to carry out a major bodily function.

* Organ: A structure made up of different tissues that work together to perform a specific function.

For example, the stomach and small intestine are part of the digestive system because they both work together to break down food and absorb nutrients.

Here are some other examples of body systems and their organs:

* Circulatory System: Heart, blood vessels

* Respiratory System: Lungs, trachea, bronchi

* Nervous System: Brain, spinal cord, nerves

* Musculoskeletal System: Muscles, bones, joints

* Endocrine System: Glands that produce hormones (e.g., pancreas, thyroid)

So, the key to determining if two organs belong to the same system is to look at their shared purpose in maintaining the body's overall health and functioning.