Fracking is a controversial topic in the United States. Protesters against fracking argue that it: reduces the price of gasoline.
pollutes the air, groundwater, and wells.
boosts domestic oil production.
raises the costs of transporting gas.

B

Explanation:

got it right on edge

the mongolian invasion of china and central asia resulted in a disruption of the silk road as the chinese garrisons lost support from the chinese kingdoms which fell under the mongols. however, as the mongols established a formal dynasty in china, the successors of genghis khan restored the garrisons along the silk road allowing the safe travel caravans again.