Answer:
Plantation labor
four million enslaved people in the U.S. in 1860, nine out of ten lived on farms and plantations (mostly cotton plantations), and half lived in the Deep South.
The historians could be wrong without proper proof to back up their so-called "facts". Therefore, they would need to study and know what they're talking about, before presenting their statements as facts.
During WW2 the military was inventing the atomic bomb then later launched it on Japan
