I would go for:
<span>North had a more widespread network of railroads available for delivering troops and supplies to the battlefield.</span>
I googled it and it said 50-100 billion
Beavers might be the most well-known animal architects, and with good reason. These prolific builders fell trees and gather sticks and mud to construct dams, which create ponds that offer predator protection and easy access to food during the winter.
The Aryans had brought the language of <span>Sanskrit to India.</span>
Answer
Hostility of business towards unions
Explanation
A Union is a society or association formed by people with a common interest or purpose. In the 19th Century the labor movement in the United States grew out of the need to protect the common interest of workers. For those in the industrial sector, organized labor unions fought for better wages, reasonable hours and safer working conditions. Later these Unions were unsuccessful in improving work conditions because of government intervention. The United States government usually supported the businesses instead of the workers/labor unions because they increased the national wealth. Hostility of business towards unions was also a factor that greatly limited them.