Why were sugar planters particularly concerned with secession?

Helen is a u.s. citizen and cpa, who moved to london, england three years ago to work for a british company. this year, she spent the entire year in london and earned a salary of $110,000. how much of her salary will she be allowed to exclude from gross income in the u.s.

Who established the peoples republic of china in 1949

Why are the majority of the world's economies mixed? what may happen to the "pure" types of economies (traditional, socialist/command, market capitalist) when they incorporate elements from other economic models?