When World War I broke out in Europe in 1914, industrialized urban areas in the North, Midwest and West faced a shortage of industrial laborers, as the war put an end to the steady tide of European immigration to the United States
The Aksum Empire was the result of two world hubs sharing their collective learning about agriculture, and rose to become a great power in the ancient world because it formed a crucial link between East and West on the supercontinent of Afro-Eurasia.
Price ceilings prevent a price from rising above a certain level. When a price ceiling is set below the equilibrium price, quantity demanded will exceed quantity supplied, and excess demand or shortages will result. Price floors prevent a price from falling below a certain level.
Well here are things you can measure in SI units: volume, mass, length, density
