I think it’s Nervous system
your answer is gonna be A
The industrial revolution brought the United States to where we are today. Specifically it helped create more jobs and easier manufacturing. It also helped the economy of the west improve greatly. With all the new inventions people started to become more creative and open to newer ideas. It also helped communication and transportation which was a big deal since we had acquired a ton of new land.
Answer: Coal
Explanation: Natural gas is basically gas that comes from nature so if you use coal it creates natural smoke or gas. Also like fossil fuels create natural gas as well.
12 is b) uncontrollable
13 is d) monetary policy