Areport issued by the concluded that there was a scientific foundation for studying marijuana as a treatment vehicle.

I believe the answer is: United States National Academy of Sciences

Marijuana has the side effect of making the users to increase their overall pain tolerance. The medical field usually use substance such as morphine to induce this situation. But many studies shows that using Medical marijuana actually give less 'bad side effect' to the patient if compared to other substance.

The correct answer is a. when they started making tools that will them in cultivating lands, they could raise crops and that made them attached to one place for a longer period of time. after that, they started domesticating animals and building their own permanent settlements that resemble the ones we have today.