>>5164101It's both you fool.
Northern Europe is dark. In some places the sun sets at like 4pm during the winter. The blue eyes help reflect more light into the eye to see better when it's dark. Brown eyes absorb light so you can see better when its bright out. Brown eyed vision, compared to blue eyes, is like wearing sunglasses.
Similarly, the blond hair allows more light to penetrate to the skin on the scalp, triggering the production of vitamin D. Hold up a white tee shirt to a lamp and see how much light is let through. Now hold up a black shirt and compare. In sunnier areas, skin turns darker because they get a surplus of vitamin D and it is more advantageous to protect yourself from the sun.
