We'll keep making vitamin d and inventing shit.

Also,I really do think immigrant groups get paler when they move to a northern country. I have a picture of me nan at school and her class was 50% Jewish. Those Jewish kids in the 1930's look like Indian kids now.

It's natural selection. Low vitamin d doesn't just make you die of things like covid more often but also effects mental health and even mental disabilities like MS.

If you have a crazy or disabled person in the family that can hold back a whole generation. In India families they will even stop a child marrying so they can spend their lives looking after a disabled family member, that's them taken out of the gene pool.

The you have the possibility the body can itself adapt its appearance to its environment.