The cholera epidemic. The others were factors, but not as serious.
C. 18 It was lowered around 1970, and is now asking to be lowered to 16
Slavery was bad because African Americans were used for many of things but didn't get treated as if they were people. They didn't have good clothes, weren't fed well, beaten, and many of other bad things. They also weren't allowed to own their own property.
