Another sign of blues is the use of harmonicas. When I hear B.B. King, or John Lee Hooker, that's what I call blues. On the whole, the distinction between jazz and blues is still nebulous. Seeda, I always find this curious about u. I would think it will be useful to you.
Jazz is improvisation and improvisation is jazz.
Please feel free to differ with me. But I dont think it is necessary. I would like to share your view as much as you would want to. And very great musicians have all at one stage been curious just like you and me. What makes them great is they keep learning, and never stop.