Final answer:
The Declaration of Independence is a critical document that declared the American colonies' independence from Britain, asserted the unalienable rights of individuals, and listed specific grievances against King George III, marking the justification for revolution and the colonies' self-determination. Option a and c are the correct answer.
Step-by-step explanation:
The Declaration of Independence is a seminal document in American history and the history of democracy as a whole. The correct answer to the question of why this document is so important and what it established is d. All of the above. It not only proclaimed the colonies' independence from Great Britain but also enshrined the unalienable rights of Life, Liberty, and the pursuit of Happiness as fundamental to its philosophy. Furthermore, it catalogued a litany of grievances against King George III, accusing him of tyranny and abuses of power, thereby legitimizing the rebellion and asserting the colonies' right to self-governance based on Enlightenment principles of equality and government by consent.
The document, primarily authored by Thomas Jefferson, was a declaration that the American colonies were free and independent states no longer under British rule. It represented a collective agreement that when a government becomes oppressive, it is the right of the people to alter or abolish it and institute a new government that would secure their safety and happiness. This assertion established a blueprint for democratic government that empowers the people and enshrines their rights as paramount.