There is nicotine in tobacco naturally, and I'm pretty sure addiction of tobacco has been reported long before the big companies got resources to add various chemicals in cigarettes.
Not to any significant amounts, and certainly not to the levels with modern cigarettes. Personally, I have never heard of any case documented before Big Tobacco that found naturally grown tobacco chemically addictive.
Also, marijuana is often blended with tobacco if I'm not mistaken, but that may be beside the point.
That's up to the smoker. A joint is normally rolled up in rolling papers. A blunt is when someone uses a cigar wrapper instead. I'm sure somewhere in the world someone mixes dried tobacco in with their weed. But, that's not a constant that can be measured...
