Positive effect is the usage of more land whereas negative effects is the control problem of that land.
<h3>Effects of settling the west</h3>
The positive effect of settling the west is that it provides America more land to use and its resources for the betterment of the economy while on the other hand, the negative effect of setting the west is that it was more land to control for the United States as well as the United States had to fight 2 wars to gain the territory.
<h3>Effects of railroads on the physical environment</h3>
The main disturbances caused by railways are air, soil and water pollution and noise which adversely affect species and organisms present in that environment.
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