B7: Subject-Verb Agreement with who, which, and that: A relative pronoun (“who,” “which,” or “that”) used as a subject of an adjective clause takes either a singular or plural verb in order to agree with its antecedent. See the following (scroll to the bottom): https://writingcenter.unc.edu/relative-clauses/
The waiters will be the ones who are there to serve you.
A lion is one animal from the wild that is especially deadly.
The teenagers were at the theater on Main Street, which is one of my favorite places in town.