Why did the American Revolution start?

The American Revolution (i.e., the American Revolutionary War) was an armed conflict during which thirteen colonies on the east coast of North America fought for their freedom and liberation from British political influence. The revolt lasted 8 years (1775–1783), and one of the most important moments was the signing of the Declaration of Independence on the fourth July, 1776.
There were several reasons that caused the start of the Revolution. The British Empire treated the American people quite harshly—as they demanded the colonies to pay a large share of the war debt from the French and Indian War—and increased their taxes.
As the British political influence was very dominant, the American people felt that they should have their own representatives in the British government, who would speak on behalf of all Americans. Many famous revolutionaries and political activists such as Thomas Paine suggested that the American people should be free and independent, as they were capable of leading and governing their nation.
Soon, many Americans began collecting weapons, and, in the April of 1775, the British soldiers and the American colonists' militia opened fire at Lexington and Concord in Massachusetts. Thus, the Revolution began.