South Caroline seceded because they were trying to hold onto their way of life that was based on slavery. They said states' rights allowed them to secede and they were scared that non-slavery states would threaten their rights.
Because it helped them gain money and popularity.
They can expand their colonies and if they expand and trade more then more people will know about trading. Expanding their colonies was inprotant and their rivals became less popular which caused decline in their trading
You didnt put a middle passage