Well, in a cigarette, the most active ingredient is ammonia. The companies claim that it enhances the flavor of the cigarette, but, it's actually highly addictive. It allows more nicotine to flow into our bloodstream making us crave more than what we want. But, also in itself, nicotine is also highly addictive, the ammonia just aids it to make the person urge to smoke.
Letters are any of the 26 letters featured in the alphabet
Characters on the other hand can include all alphabetical letters however it DOES include symbols such as ,*/,?, etc. It can include numbers, underscores, dashes and emoticons as well.
