The bolded pronoun in the given sentence is the word "which". This pronoun is an example of an interrogative pronoun. Interrogative pronouns are pronouns that are used to introduce a question. The antecedents of interrogative pronouns are unknown because it is what is being asked in the sentence that is missing.
........Bruh it's the wind....you answered your own question <span />
An example of a periodical is People Magazine.