Systems have two or more parts interacting within some boundary. In living systems, the relationship among the parts matters. If essential elements are added or taken away, the behavior of the system changes. Removing the heart from the body changes the way the body works.
What is a system? What’s not a system?
Take a look at the following list. Which of the following would you characterize as “systems”?
A bowl of nuts
A soccer team
A vacuum cleaner