A particle doesd no know how many electrons atre needed to make up an element, but when the ratio of +/- is 1:1, the element likes this because it feels stable. And to answer the question of DNA and its unraveling, well you had better take a bunch of coures in biochemistry, because we, as humans know that it works but do not really how life works. The big bang happened billions of tyears ago, which formed our planet, suposedly, which formed the rocks on the planet, which formed dirt, which formed....... Life did not just happen over night, but it did just happen. maybe we are not yet smartenough to understand this concept, but who knows, a few million years ago we were just primates, look how we have evolved!