Answer:
These two cannot be compared, because they are not correlated in anyway. There are reasons why each have it's own color.
As of the sky being blue, the refraction of the light causes the blue light to scatter, allowing us to see the light "blue". All other lights are absorbed, and so we cannot generally see it.
The Apple is Green, not only because of genetics, but because, when light hits the object (in this case the apple), it absorbs all other colors, while reflecting the color green, allowing us to see the color green.
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