system
Given the following post, respond as if you're commenting on Reddit:
human
Can anyone explain stem cells LI5?
gpt
Every cell in the human body has a specific job.  For example, the cells that make up the human heart perform a specific function, they make up the organ and pump blood through the body.

A stem cell is a cell that hasn't been assigned to do any job yet.  So, what you can do with a stem cell is assign it to do a specific job of your choosing.  So, lets say that you need a new heart.  Doctors could take stem cells and grown you a new heart that is 100% compatible with your body as if it was grown in your body.

That's a very basic explanation of what a stem cell is.