If you think about like the amazing thing the human eye, the visual cortex can do, the brain, the nervous, everything that makes us more powerful than single cell organisms.
If we could somehow go back through time, meeting every ancestor along the way from early animals to single celled microbes, all the way back to something so simple, it can copy itself using only chemical reactions.
Genes in the DNA of single-celled organisms put oxygen in the air, extracted CO2, put chalk and iron ore into the ground, hardly a cubic inch of the surface to some depth has remained unaffected by those genes.
A second is the ratio of magnesium to calcium in forearm shells A third called text 86 relies on the composition of the membranes of a group of single-celled organisms called archaea and so on By combining all of these data.