It did arise by itself. There was not a scientific basis for this until the discovery of evolution. It explains how an iterative process can produce complexity out of simplicity.
No, it does not, when examined carefully. What factor would you nominate that causes this interaction? Of note is that these interactions are not generic but specific. Evolution comes from Genesis, and is an after the fact process - meaning there is no evolution without an already existing construct: otherwise what will evolution evolutionise?
The universe was not fine-tuned for life, life is fine tuned for the situation it evolved in.
Yes it was, and this is described in Genesis. Prior to life, there were a host of anticipatory actions, without which life could not occur. These are expressed by the fundamental examples:
LIGHT SEPERATION FROM DARKNESS
WATER SEPERATION FROM LAND
DAY SEPERATION FROM NIGHT.
These critical seperation factors are seen on earth, where life emerged - they are not seen in the other planets. The metaphor applying is:
THE DINNER TABLE IS READY FOR THE GUESTS.
Here is one question for you then. If complexity needs complexity to exist, where did the original complexity come from?
Yes, good question, but well factored in. Obviously, what you are referring to is a program, as in a chip in your mobile. These are forces which enable a particle to behave in a certain way, and to pass on this program in repro. The word described in the Hebrew is an ancient and mysterious word, loosely translated as 'SEED' - which can refer to essence; program. We know today our bodies contain recepticles for programs, such as DNA and genes - but these are not random performing data - they perform specific tasks with a pre-determined end result. Each group of cells perform only immediate and specific actions - meaning they are programmed for specific tasks. Basically, what you call NATURE are the networks which conduct and process these tasks on micro and macro levels throughout the universe. Here, nature is akin to the wiring in your mobile chip: it does not negate the chip maker but affirms it.