What is mouse ?

What is mouse?
Mouse is a pointing device. Mouse is used to point and select items.  Mouse are classified in 4ways.
Two button mouse
Three button mouse
Ball mouse
Optical mouse

In present time we don't use two button mouse and three button mouse. Ball mouse is also used in few places. All are widely used optical mouse.
Two button mouse has two buttons on it.
Three button mouse has three buttons on it.
Ball mouse has a ball inside it. Ball mouse also called mechanical mouse.
Optical mouse has a light inside the mouse.