Final answer:
A run-on sentence is a sentence that consists of two or more independent clauses without proper punctuation or conjunctions.
Step-by-step explanation:
A run-on sentence occurs when two or more independent clauses are joined improperly, without the appropriate punctuation or conjunctions. In the given options, the sentence 'Ms. Williamson turned left, she yielded to oncoming traffic' is a run-on sentence because it consists of two independent clauses joined by a comma without a coordinating conjunction or proper punctuation.
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