Just like airborne viruses today: Sneezing and coughing
Economic and trade was the important thing in the history every people trade their things
I can only write this much
I believe it would be the industrial revolution and the civil rights movement.
The industrial revolution make companies able to improve their production with more machinaries and less slave labors. Which make the usage of slavery became less and less popular in the north. It also allow the construction of railroad for easier distribution system and The civil right movement bring up equality issues between race majority/minority to the law.
C. A return to normalcy.
Explanation:
The great depression ended earlier, The Us just wanted a more peaceful country.
I know she died of a heart attack at 53 years old at Lincoln Hospital in the Bronx in New York.