The passage below contains a blank. Fill in the blank with the punctuation mark that correctly sets off the nonessential element, ensuring the sentence conforms to the conventions of Standard English.
Answer:In 1915, German mathematician Emmy Noether proved a landmark mathematical theorem linking differentiable symmetries and physical conservation laws. The theorem—which quickly became a cornerstone of modern theoretical physics【—】established that every continuous symmetry of a physical system corresponds to a specific conserved quantity, such as energy, momentum, or electric charge.
Answer
The blank must be filled with an em dash (—) to match the em dash that introduces the nonessential clause.
The correct punctuation is an em dash (—). Nonessential elements, such as the relative clause 'which quickly became a cornerstone of modern theoretical physics,' must be set off from the main sentence with a matching pair of punctuation marks. Since the clause is introduced with an em dash, it must also be closed with an em dash to maintain grammatical symmetry.
Step-by-Step Solution
Key Concept
Punctuation of Nonessential Elements
Estimated Time:1m 0s