In the 1800s what new technology nations build and maintain their empires?

Explain one example of how the u.s has struggles to balance energy independence and environmental

After the success of the sputnik launch, the united states feared that they would never be able to launch their own satellite, the ussr had used technology developed by the united states, the soviets had superior nuclear capabilities, that any future us satellites would not be as successful.

You are traveling to japan and need japanese yen how much jpy could you get for $200