PP1 (Shorter) Verbal Section 2 (Hard) Q5
The Right Answer
This is a Detail, or Factual, question, as indicated by the phrase "According to the passage." Moreover, this is a Multiple-Select problem, in which we must choose at least one answer but up to three. Thus, there are a total of seven possibilities: A, B, C, AB, AC, BC, or ABC.
In rephrasing the question, we notice that it asks us to identify causes that contribute to the elliptical shape of extrasolar planets' orbits. Let's analyze the evidence from the passage.
Piece of Evidence 1: If two planets form in close orbits, one will be scattered inward (toward its star), the other outward.
In looking at the answer choices, we see that this evidence matches with the first answer choice: The planets' formation in close proximity to other planets.
Piece of Evidence 2: They will likely then travel close enough to neighboring planets to disturb their orbits also.
In looking at the answer choices, we see that this evidence matches with the second answer choice: The gravitational influence of planets whose original orbits have been disturbed.
Thus, the correct answers are A and B.
The Wrong Answer
The last answer choice (The gravitational influence of comets) is not supported by the evidence. The passage informs us that by observing comets in our solar system, scientists received a "clue" as to why most known planets have elliptical orbits. The evidence does tell us that the comets were affected by the gravity of the planets, but not that this occurred the other way around. Also, from a purely logical point of view (and using some outside knowledge), how could a comet meaningfully affect the orbit of a planet? Comets are tiny in comparison!