what is the difference between the Geographic coordinate, transformed coordinate and screen coordinate [duplicate]

Question

What is the difference between the Geographic coordinate, transformed coordinate(projected) ,cartesian coordinate, and screen coordinate? Is there a live example?

And what is the association between them? For example, on geographic coordinate will have one or more transformed coordinate?

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The following is a .prj file from this post:

PROJCS["Lambert Azimuthal Equal-Area",
       GEOGCS["GCS_WGS_1984",
              DATUM["D_WGS_1984", SPHEROID["WGS_1984", 6378137, 298.257223563]],
              PRIMEM["Greenwich", 0],
              UNIT["Degree", 0.017453292519943295]],
       PROJECTION["Lambert_Azimuthal_Equal_Area"],
       PARAMETER["false_easting", 0],
       PARAMETER["false_northing", 0],
       PARAMETER["latitude_of_origin", 0],
       PARAMETER["central_meridian", 20],
       PARAMETER["xy_plane_rotation", 0],
       UNIT["Meter", 1]]

Then what confused me is that Lambert Azimuthal Equal-Area is the name of the projection coordinate system, and it specified the geographic coordinate system here(GCS_WGS_1984),why? Does it mean that this projection is only fit for the GCS_WGS_1984 geographic coordinate? As far as I understand, the projection have nothing to do with the geographics coordinate.

For example,given a geographics coordinate system GCS_WGS_1984.

Now I can use different type of projection(like UTM, and Lambert Azimuthal Equal-Area in the post) to transfrom the geographics coordinate to projected coordinate. So the projection is not bounded with the geographics coordinate system. Isn't it?