In the following sentence, is "who" the subject, predicate nominative, direct object, indirect object, object of preposition, possessive, or appositive? Please use this ticket for the child who you think is most deserving.
The relative pronoun "who" is the subject of the relative clause "who you think is most deserving".
A relative clause is a group of words with a subject and a verb, but is not a complete sentence on its own, that "relates" information about its antecedent.
The relative clause "who you think is most deserving" relates information about the antecedent "child".
The subject of the clause = who
The verb = is deserving