1) Absence, despite centuries of looking for it, of any verifiable instances of spontaneous generation. (The origin of life from non-life as a mundane process of nature.) Biological organisms only come from preexisting biological organisms.
2) Various considerations, e.g. the Second Law of Thermodynamics, indicating that the universe cannot be infinitely old. If the universe had a beginning, and the solar system, and the earth, etc, then so must biological life.
Well, that's only two. But if life does not spontaneously spring into existence, and biological life has not always existed, then it must have started at some point. It either happened by some sort of creation, or by some sort of chemical evolution. In either case it arose from a NON-BIOLOGICAL source, Q.E.D. Unless you want to argue that God is a biological organism!
"Out of curiousity, tell me the three CONCRETE observations that persuade you that all living things evolved from non-life and/or a strand of rna/dna."
Since life has no where else to come from, it must have been created from non-living elements. Even if God created everything including life, life would still have been created out of non-living materials (humans are made of atoms and quarks, non living materials yet still possess life). I tend to believe life was created from the chemicals/materials available on the planet (what else is there?) given the right combination of temperature, pressure, atmosphere and light.
I feel if you repeat these conditions on other planets with similar orbits around similar suns with similar chemical makeups and other conditions I described above you will most likely get primitive forms of life arising "spontaneously".