In Ellingham diagram, where we plot  $\Delta G^0$  for the formation of oxides of various metal with respect to temperature, which of the following statement(s) is/are correct?
I. A metal with higher slope of curve gets always oxidized.
II. A metal with lower slope of curve never get reduced at any temperature.
III. The slope of the curve for some metal changes after particular temperature because of phase change of metal.
IV. If two metals have same slopes, the one which has greater y-intercept usually get oxidized by the other one.
V. If two metals have same slopes, the one which has greater y-intercept usually get reduced by the other one.