Answer:
The phrase that makes the thesis statement wordy is highlighted below:
Elementary schools should not allow cell phones to be brought by students.
Explanation:
Wordiness happens when an author uses more words than needed to express a thought. In the sentence we are analyzing here, the phrase that causes wordiness is "to be brought by students." The reason why it is wordy is that this information is quite obvious. Mentioning it in the sentence is unnecessary. The sentence still makes sense and expresses a complete thought without it:
Elementary schools should not allow cell phones.
