The greatest advantage of United States in world war II was its ability to rapidly transition from peace to war and mass produce weapons and war equipment at a colossal scale. This was so effective that the USA was able to make up for time lost, and the nation was able to effectively train the necessary forces and then exert a massive material superiority.
America was able to build up an air force that came to dominate the skies, and with this air superiority, it was all but over for the enemy, the Axis forces.
Answer:
Irrigation highly depends on water sources in order for it to work. Without clean water, crops will die and wither. And polluted water causes filthy and contaminated trade routes, which are unsafe to travel across. Also, education has water fountains in the buildings (not sure now cuz of corona but clean water is used in school buildings.
Explanation:
A. Spanish conquistadors bring their horses with them across the Atlantic. Some horses escape or swim to shore after a ship sinks. The Plains Indians become expert horsemen and buffalo hunters.
This was certainly not intentional since hardly the conquistadors would want their enemies to be stronger.
B. B. Rats are aboard European ships coming to the Americas. The rats spread disease and hunt unknown numbers of smaller animals to extinction.
This is hardly intentional. Rats were almost unavoidable back then and the Europeans just did not care much about them. They weren't thinking about how the rats would cause trouble in the Americas. They were "just rats".
So the only intentional one is:
C. Columbus brought pigs to the Americas on his second voyage. The pigs provided a valuable source of food for a growing population.
Columbus brought pigs for them to serve as food eventually and so they did.
I beleive it's Nation Y imports precious metals, minerals, and agricultural products from country X.
But I'm not 100% sure.