Explanation

Creating a filter: Here we have a sentence in which a supporting clause adds distance between the grammatical subject and grammatical verb of the main clause, making them harder for our ears to place next to each other. When evaluating the subject and verb of the main clause, you can omit other clauses and modifying phrases from the sentence. The grammatical subject is "structure." The word "dinosaurs" is not the grammatical subject because it's an object of the preposition "of" in the phrase "of bird-hipped dinosaurs." The grammatical verb is "help," and putting them together we have "the structure help," which is incorrect. We need a grammatically singular verb, "helps." That's our filter.

Applying the filter: (B), (C), and (E) have it, so they remain potential correct answer.

Finding objective defects: We compare these three answer choices further. Choice (C) has the garbage phrase "paleontologists believing." As we discussed in "Food and Beverage Partner," the gerund or participle construction with "-ing" is often unnecessary. Choice (E) starts with the word "with" and ends with the word "they." We can pick on either difference; the pronoun difference is easier to check. What is that pronoun intended to refer to? Bird hipped dinosaurs: they evolved independently of other dinosaurs. So, actually, (E) looks good, while (B) has a pronoun error. The correct answer is (E).