Answer: Z- buffer is the technology that is used in computer graphics field , it is also known by the name of depth buffering.It is used for checking of the visibility of a object in particular scene. It determines the object's position whether are in front or backward with respect to each other in a 3D view. It is used when there is an object that has been projected on the screen , then depth or z-value of the produced pixel gets stored in the z-buffer .