Answer:
The introductory sentence states the Declaration's main purpose, to explain the colonists' right to revolution. In other words, “to declare the causes which impel them to the separation.” Congress had to prove the legitimacy of its cause. It had just defied the most powerful nation on Earth.
Step-by-step explanation:
The main purpose of America's Declaration of Independence was to explain to foreign nations why the colonies had chosen to separate themselves from Great Britain. The Revolutionary War had already begun, and several major battles had already taken place.