Final answer:
The Second Continental Congress elected George Washington as commander-in-chief, accepted Thomas Paine's 'Common Sense', and drafted the Declaration of Independence.
Step-by-step explanation:
The Second Continental Congress was significant for several reasons. Firstly, it elected George Washington as the commander-in-chief of the Continental Army, which played a crucial role in the Revolutionary War. Secondly, the Congress wrote and accepted Thomas Paine's influential pamphlet, 'Common Sense', which helped in swaying public opinion towards supporting independence. Lastly, the Congress drafted and adopted the Declaration of Independence, officially declaring the American colonies' separation from Britain.