This is an intriguing sentence since the answer,choices include two arcane words, augmented and meliorated. A good strategy for questions like this is to use the process of elimination on the
answer choices. First, look at what the sentence implies, paraphrase it, and predict the answer: “The zookeepers are ‘changing’ the exhibit to handle more visitors.” All the answer choices except (D) and (F), maintained and neglected, express change, so eliminate those two. Of the remaining choices, (A) and (E), abridged and truncated, mean “to make shorter,” which, when applied to the sentence, wouldn’t help the exhibit accommodate more traffic. The final choices are (B) and (C), which are two high-level vocabulary words (meaning “added to” and “improved,” respectively) and the correct answers.