Here is the question atheists can't answer...
So, the correct answer is, "
I don't know yet." (That's the correct answer for everyone, by the way)
But, are we being asked to make a bet? Okay then, that changes it, doesn't it? My bet:
Abiogenesis occurred on this planet from an environment of hydrocarbons banging into water and into each other for hundreds of millions of years. Organisms eventually evolved into cellular organisms, then into multi-cellular organism. The many and varied mechanisms of evolution acted on all of the organisms of Earth, eventually leading to the evolution of the human species.
In a nutshell.