Answer:
Because Mexico–U.S. migration represents the largest sustained migratory flow between two nations worldwide, much of the theoretical and empirical work on migration in the Americas has focused on this single case. Yet in the past few decades, migration has emerged as a critical issue across all nations in Latin America and the Caribbean. Indeed, over the past fifteen years, this region has changed its historical position from a net migrant-receiving region to one of the leading sending areas of the world.
Answer:
Correct answer is through intelligence about the Soviet nuclear program
.
Explanation:
First two options are not correct of course because this led more to the strengthening of economy of United States, and was not pointed towards the Soviet Union.
Third option is not correct as this was related more to their space race that started during the 1950s.
Last option is correct as both countries were espionage each other which in some cases almost led to the war between two countries.
Answer:
I'm sorry I don't know it.