Show[
 ContourPlot3D[{f == x, g == x^2}, {g, 0, 4}, {x, 0, 2}, {f, 0, 2},
  AxesLabel ->
   Flatten[Style[#, 12, Italic] & /@ {"g(x)", "x", "f(x)"}],
  Mesh -> None, ContourStyle -> Opacity[0.5],
  ViewPoint -> {1.88, -2.45, 1.29},
  ViewVertical -> {0.45, -0.57, 0.67}],

 ListPointPlot3D[Table[{t^2, 0, t}, {t, 0, 4, 0.001}],
  Filling -> Bottom, PlotStyle -> PointSize[Tiny]]
 ]