The American people were strongly independent. They wanted to do things for themselves. Great Britain was a long way away. The American people didn't want people an ocean away telling them how to live their lives. The British government decided to make the American colonies pay a large share of the war debt from the French and Indian War. Through the Sugar Act, Stamp Act, and other taxes, the British tried to collect taxes that the American people considered harsh. The American people also thought that they should be able to send their own people to Britain's Parliament or at least vote for Britain's lawmakers. The combination of the harsh taxes and the lack of an American voice in Parliament gave rise to the famous phrase "taxation without representation." Patrick Henry, Thomas Paine, and others called for an independent America, colonies free from British rule and interference. Americans started stockpiling guns and ammunition in violation of British laws. Their defense of such a stockpile led to the shots fired at Lexington and Concord and the beginning of the Revolutionary War.
Most research uses both primary and secondary sources. They complement each other to help you build a convincing argument. Primary sources are more credible as evidence, but secondary sources show how your work relates to existing research.
Because the south in large part were built on slaves. They didn't have factories or anything like the north did. They had cotton and assorted vegetables. In large part many will say that is also what lost them the war.