World war 1 was a cause of the great migration.
The correct answer is C. By forming trade blocs
Explanation
A trade bloc is an agreement between different nation through which certain barriers such as tariffs are eliminated or reduced, which implies trade between the countries or nations that are part of the block is cheaper, this benefits the economy of the countries participating as the economy grows. Also, trade blocks imply cooperation of nations as they reduced or eliminate barrier and support each other economy as all of them have trade benefits, because of this trade block imply nations cooperate economically.
It provided reliable resources such as food and water
The average temperature are highest near the equator and get colder toward poles.
