Computer Mouse, TrackballsA computer mouse is a small, hand-held input device that is used to control the cursor on a computer screen. It typically has two buttons and a scroll wheel, and is moved over a flat surface to move the cursor in the same direction. A trackball is a similar type of input device, but instead of moving the entire mouse, the user moves a ball on the top or side of the device with their thumb or finger to move the cursor. Both types of devices are commonly used with desktop and laptop computers, and are an essential part of the modern computing experience. They are used to select and interact with objects on the screen, such as icons, buttons, and menus.