A mouse

Not the rodent!

The purpose of a mouse is...

A mouse is used to click on things on the screen of a laptop or computer.

A ball-style mouse is made up of a mouse wheel, a little rubber ball, a switch that detects the movement of the two buttons, the two buttons (of course!), a wire that connects to the computer, analog chips (turn button-pressing into digital signs the computer understands), X- axis and Y-axis wheels and many, many more other parts.