The answer would be that light can be reflected or refracted
Napoleon’s conquest spread new ideas from the French Revolution throughout Europe
The slave trade between Western Africa and the America's reached its peak in
the mid-18th century when it is estimated that over 80,000 Africans annually
crossed the Atlantic to spend the rest of their lives in chains.
Congress
I hope that's the correct answer
There were lots of foreign changes that presented challenges for the US. I'll give you a few examples from different time periods. First would be when England wanted to tax the Americans in the Revolutionary period. They did this to try and restrict America's freedom. Another example would be that Russia had spies during the cold war period. This was to gain intelligence of the US war plans. Also when Germany sent the Zimmerman Telegram to Mexico during the WWII period. This was to get Mexico to launch a surprise attack on the US.
