One of the more frequent challenges I get from non-theists is the following: “If there is a God who wanted to create a home for human beings, why would he create hundreds of billions of useless galaxies?” The quick answer is that, given the laws of physics God chose for the universe, it is not possible to make a planet on which humans can live and thrive without the hundreds of billions of galaxies. In fact, it is not possible for any kind of physical life to exist without hundreds of billions of galaxies.
That is irrespective of whether or not there is anyone Out There.
Without carbon, life is impossible. However, fine-tuning the universe for the existence of carbon is not sufficient; unless the quantity of carbon in and on a planet is also fine-tuned, physical life—and certainly advanced physical life—will not be possible. A planet with too little carbon will not have a sufficient supply for life chemistry to function. A planet with too much carbon will possess a life-suffocating atmosphere (lung failure occurs at air pressures exceeding three times Earth’s) filled with powerful greenhouse gases. Hugh Ross, “The Miracle Elment” at Salvo