Please Help!!?

Anything can be called a system, so you need to specify what you are talking about.

Mechanical system: A ball between two books is a stable system. If the ball is pushed to one side, its weight will pull it back to the center position. A ball on one book is an unstable system. Any random vibration might start the ball rolling and there is nothing to return it to center. A ball balanced on a wire is a chaotic system. If for any reason it moves, it will instantly fall off the wire in that direction.