Which of these is necessary first for LIFE?

I would say E an energy source, if you think about it... it cant be B really because weeds grow in the cracks of cement where there is no soil... and as far as the excessive rainfall and ground water...tell that to the plants in the desert here in Vegas lol... as far as A goes...CO2 is needed for plants, as far as methane, ammonia, and H go not so sure about that... and the ozone layer to block UV rad...there have got to be bacteria that can withstand all sorts of levels of UV radiation...prions for instance can withstand the temperatures of an autoclave... so I dont see why that cant be the same for UV rads...and if you think about it... nothing can grow without an energy source, whether it be something as huge as the sun to something as small as mitochondria...but yeah... hope this helps = )