Special Agent Entrance Practice Exam

The selection of "Across" as the correct answer identifies it as a preposition, which is a word that typically describes relationships between elements in a sentence, particularly in terms of time, place, direction, or manner. Prepositions are used to introduce prepositional phrases, which provide additional information about how an action is being performed or the location of an object.

In contrast, "A dog" is a noun phrase, representing a subject or object rather than a relational term. "Beautiful" serves as an adjective that describes a noun, indicating quality, while "Quickly" functions as an adverb, describing how an action is performed. Thus, "Across" stands out as the only option that fulfills the function of a preposition, linking actions or objects to certain conditions or locations.