Answer:
No.
No.
The x and y dimensions tell where to place objects within the panel. This is like graph paper, except the (0,0) location is the upper left corner of the drawing area, not of the full screen. Increasing y values move down the area.
Distance is measured in pixels. A pixel is one of the graph paper squares that the video screen has been (conceptually) divided into. If your monitor is set to a resolution of 800 by 600, then the whole screen is divided into 800 horizontal squares and 600 vertical squares. An frame will usually cover only part of that area, perhaps an area 300 horizontal by 150 vertical. It is the responsibility of the graphics card and its driver to implement this idea of graph paper on the actual electronics of your computer system.
A pixel is not one of the little, glowing dots of phosphor on the monitor screen. Depending on the resolution you are using, an image pixel may correspond to several of these dots or a fraction of one dot.
Say that frame is displayed in a rectangle of 300 by 300 pixels. Does the actual size (as measured in inches) of this area depend on the resolution of the monitor?