Final answer:
The Second Continental Congress ratified the Declaration of Independence on July 4, 1776, marking the formal decision of the American colonies to seek independence from Britain.
Step-by-step explanation:
The group that ratified, or agreed to, the Declaration of Independence was the Second Continental Congress. This assembly of colonial delegates convened in response to the escalating conflict between the American colonies and Great Britain.
After the failure of the Olive Branch Petition and the outbreak of war (marked by the clashes at Lexington and Concord), it became clear to the Congress that reconciliation with Britain was no longer feasible. As a result, Congress appointed a committee to draft a statement of independence.
On July 4, 1776, the Declaration of Independence was adopted, marking the American colonies' formal decision to separate from Britain and their entry into the War for Independence as a new nation.