Better yet, here's your answer.

cannabis has what are called psychoactive chemicals, the main one being "tetrahydrocannabinol" or THC for short. When you smoke a joint, the THC goes into your lungs, then into your heart which pumps it into your bloodstream which then takes it directly to your brain. When you smoke marijuana, it only takes a few minutes for the THC to get to your brain, whereas if you eat it, it would take a little longer because it has to pass through your digestive system first. Once it's in your brain, the THC activates what are called "receptors", and gives you the feeling of being high. In short, marijuana changes the physical and chemical balance in your brain and this is what people refer to as a "high".

More complicated facts about the brain, go here: http://www.thebrain.mcgill.ca/flash/index_d.html

Information above found here: http://www.drugwise-droguesoisfute.h...arijuana_e.asp

If you're going argue about true "facts" of yours, at least back them up.