What is the term for a short statement about history that has not been yet been proved

Transcontinental railroad was the most effective way to travel.

Britain altered native american societies culturally because some of the indian tribes were friends with the british and thought them their culture and the british did the same.some of the tribes didn't like the british and fought against them with france, some tribes didn't want anything to do with the europeans and left them alone.trade with the british changed them economically because they were now trading food for things like guns and blankets.