Final answer:
True, the phrase 'shot heard round the world' is from Ralph Waldo Emerson's poem 'Concord Hymn' and refers to the start of the American Revolutionary War.
Step-by-step explanation:
The phrase “shot heard round the world” is indeed from the poem “Concord Hymn” by Ralph Waldo Emerson. It refers to the first shot fired at the Battle of Lexington and Concord on April 19, 1775, which started the American Revolutionary War. The battle is marked as the moment the colonies effectively stood against British rule, igniting the revolution and eventually inspiring other nations, such as France during the French Revolution. This foundational event, often mythologized, lives on through Emerson's poem, elaborating on the significance of the clash between the British troops and American militiamen.