Final answer:
The Second Continental Congress in 1775 decided to form the Continental Army, electing George Washington as its leader, signifying the colonies' move towards independence.
Step-by-step explanation:
One significant decision made by the Second Continental Congress in 1775 was the formation of the Continental Army. This decision was a direct response to the hostilities that had begun at Lexington and Concord, marking the start of the Revolutionary War. Although there were hopes for reconciliation, the conflicts had escalated to a point where the colonies felt compelled to organize a unified armed force for their defense against British troops. The Congress appointed George Washington as the commander-in-chief of this newly formed army, cementing their commitment to a united colonial resistance against British tyranny. This marked a crucial step towards American independence and the fight for self-governance.