Here's why:
* Relative Pronouns: Relative pronouns (like "who," "which," "that") connect a relative clause to the main clause. They refer back to a noun or pronoun in the main clause, called the antecedent.
* The Clause: The relative clause in this sentence is "who heard the news." This clause modifies the noun "everyone."
* The Antecedent: The antecedent is the noun or pronoun that the relative pronoun refers to. In this case, "who" refers back to "everyone."
Therefore, the antecedent for "who" is "everyone".