Answer:
Registering to vote in one's home
Hope this helps you
The correct answer should be Advances in Technology and Industrial revolution
Mexican-American war happened in the 40s so that's before 1860, while a war with Spain occurred in 1898 which is after the mentioned period. They did advance in technology exactly due to the industrial revolution. An agrarian revolution. An agricultural revolution didn't happen in the US because of the Long depression that slowed it all down.
The answer is people of the Ghana Empire practicing Islam after interacting with Arab traders
They would be around 65 to 75 or even older