The total amount of a product available in a market at a given price is called the supply.
There are a lot of factors that affect supply such as the price of the product, price of similar goods in the market, price of inputs, and the number of suppliers.
This question is incomplete because the options are missing; here is the complete question:
How did railroads spur economic growth and create new markets for products after the Civil War?
A. By linking the nation together
B. By reinvesting in other industries
C. By bringing immigrants west
D. By providing railroad land to settlers
The answer to this question is A. By linking the nation together
Explanation:
The creation of new railroads and the expansion of old railroads after the civil war was key in the economic growth and prosperity of the U.S. This is because the railroads connected or linked many territories that were previously isolated. This implied goods and raw materials could be easily transported, which increased production and trade. Moreover, there were new markets as territories connected integrated in trade. According to this, option A is correct.
It opened up a second front in the war, which lead ultimately to the defeat of nazi Germany.
D. A primary source comes from someone who has actually witnessed the event, while a secondary source is not based off of firsthand experience.