How to show these two plots “clearly”?

The following two plots are not visible when shown togather:

  tr1 = With[{a = 0.1},     Composition[TranslationTransform[{0, 0, a}],      ScalingTransform[{Sqrt[1 - (2 a - a^2)],        Sqrt[1 - (2 a - a^2)], (1 - (2 a - a^2))}]]]; plot1 = Region[TransformedRegion[Sphere[], tr1],    PlotTheme -> "Detailed", PlotRange -> {{-1, 1}, {-1, 1}, {-1, 1}},    AxesOrigin -> {0, 0, 0}, AxesStyle -> Directive[Black, 17],    AxesLabel -> {x, y, z}, AxesEdge -> Automatic]  tr2 = With[{a = 0.2},     Composition[TranslationTransform[{0, 0, a}],      ScalingTransform[{Sqrt[1 - (2 a - a^2)],        Sqrt[1 - (2 a - a^2)], (1 - (2 a - a^2))}]]]; plot2 = Region[TransformedRegion[Sphere[], tr2],    PlotTheme -> "Detailed", PlotRange -> {{-1, 1}, {-1, 1}, {-1, 1}},    AxesOrigin -> {0, 0, 0}, AxesStyle -> Directive[Black, 17],    AxesLabel -> {x, y, z}, AxesEdge -> Automatic]  Show[plot2, plot1] 

How can one plot these with different colors and adjust the transparency such that they are visible neatly?