A slight hair splitting here with your phrasing. You've got it backwards. DNA doesn't "evolve to addapt". Variations get copied and passed down except for thos

A slight hair splitting here with your phrasing. You've got it backwards. DNA doesn't "evolve to addapt". Variations get copied and passed down except for those within individuals that didn't reproduce. Sometimes an entire lineage doesn't reproduce, that's extinction. So, there's no "eventually". Our bodies may not be "fully" understood. But there's no points for an argument from ignorance. Still there may be people that live to 90 without getting dementia in heavily polluted cities. However, that's down to natural variation.