The answer is personal experiences, for this term is the most important aspect if defining psychology, according to psychologist. It is because personal experience is one of the factors of having to determine things of how psychology will likely occur or what will likely trigger and help in studying it.
Because the slaves are what worked the economy, while everyone else did nothing. Without the slaves the entire thing would collapse because slave owners would not want to work.
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Its A... I like 99.99% sure it's A. because you have to pay back what you borrowed from the banm