- Concerns over which of the following led to the Soviet intervention in Afghanistan: PA) Border security
B) Free trade
C) Possession of nuclear weapons
D) Environmental threats

How did the completion of the transcontinental railroad change the lives of american citizens? a-it increased the wealth of all americans and enabled them to travel more.b-it made cross-country travel too expensive for ordinary americans.c-it decreased the safety of americans who moved to settle the plains.d-it shortened travel time between the east and west for all americans.