In which underlined adjective clause is the relative pronoun used as the object of a preposition? I saw a dog whose sled left without him. The part of Alaska that is within the Arctic Circle is cold most of the year. The explorer whom I met last year has never been to the North Pole. The climate is one in which little foliage can grow.

Explanation: A relative pronoun is a type of pronoun that often introduces dependent clauses in sentences. The relative pronouns are: who, whoever, whom, whomever, that, which, when, where, and whose. The object of a preposition is a noun, noun phrase, or pronoun that follows a preposition and completes its meaning. From the given sentences, the one that has a relative pronoun as the object of a preposition is option D: "The climate is one in which little foliage can grow" the relative pronoun is "which" and it is part of the object of the preposition "in."