What is more addicting alcohol or tobacco?

Tobacco is much, much more addictive than marijuana. The active ingredient in tobacco (nicotine) is physically addictive (meaning, there are physical withdrawal symptoms when you quit smoking). The active ingredient in marijuana (THC) is NOT physically addictive.

Furthermore, many studies have shown that nicotine is at least as addictive, if not more addictive, than heroin. The same cannot be said of marijuana.