Answer:
Formaldehyde can be added as a preservative to food, but it can also be produced as the result of cooking and smoking. Formaldehyde also occurs naturally in the environment. Humans and most other living organisms make small amounts as part of normal metabolic processes. Formaldehyde is also a byproduct of combustion. When burning natural gas, kerosene, gasoline, wood, or tobacco, formaldehyde is produced. Automobile exhaust is a common source of formaldehyde in our environment. Tobacco smoking in the home is another source of the chemical in the indoor environment.
Explanation:
During the 1800's, transportation in the form of railroads improved trading and selling of goods and services in the U.S. The railways created major cities along their route and allowed not only goods, but people to go west.
Farming in the west was important during this time period. Before railroad systems, people usually lived, worked, and farmed close to the coastal areas, so travel and shipment of goods was easier. Railroads changed that. Traveling via train was easy and cheaper.
