I believe the answer is C because the court ruled that he was not a free man because 1. He was a slave and the court believed that if you were black, then you were not a n American Citizen and 2. He was the property of his own. Sorry, I could be wrong.
Although the 1800s in the United States seems like it was limited in opportunity by today's standards, it was much easier to make a living during this time in US than it was in China.
Answer: They do this through a process called "mutation".
It could also be genetic modification, depends on what your text or teacher teaches you tbh.