Answer: A
Explanation: I could be wrong but just went over this yesterday hope it helps
D. They had no immunity to diseases brought by European explorers and settlers :D
Answer:
They increased exponentially.
Explanation:
With Ford's use of the assembly line, they could make exponentially more cars than before, which would in turn lower the price of each car.
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.
Learn more about railroads here: brainly.com/question/2724028
