Question 202·Hard·Rhetorical Synthesis
While researching a topic, a student has taken the following notes:
- In the late 1960s and early 1970s, astronomer Vera Rubin measured the rotation curves of spiral galaxies.
- She found that stars far from galactic centers orbit at nearly the same speed as stars close to the centers.
- These results conflicted with predictions based solely on the gravitational pull of visible matter.
- Rubin’s observations provided persuasive evidence for the presence of unseen “dark matter.”
- Her work led to the broad acceptance of the dark matter hypothesis within the astronomical community.
The student wants to craft a sentence that highlights the scientific impact of Rubin’s research. Which choice most effectively uses relevant information from the notes to accomplish this goal?
For rhetorical synthesis questions, identify the exact purpose named in the prompt (here, “highlight the scientific impact”), then choose the option that best combines the most relevant notes into a clear cause-and-effect statement. Prefer answers that use specific evidence from the notes and explicitly connect it to the stated consequence, while avoiding answers that are vague or that fail to synthesize multiple key bullets.
Hints
Focus on the task word: impact
The question asks for a sentence that highlights the scientific impact of Rubin's research. Ask yourself: which notes describe not just what she did, but how it changed astronomers' understanding?
Locate the “effect on the community” in the notes
Look closely at the last two bullet points: what do they say Rubin's observations were evidence for, and how did the astronomical community respond?
Match both finding and consequence
Eliminate choices that only talk about her measurements or only talk about influence without explaining what specifically changed. Look for an option that combines her surprising result with the change in scientific thinking.
Watch for unsupported claims
Be careful of any answer that introduces details about her influence or reputation that are not explicitly stated in the notes.
Step-by-step Explanation
Identify what the sentence must accomplish
The sentence must emphasize scientific impact—not just what Rubin measured, but how her findings changed astronomers’ understanding.
Pull the cause-and-effect from the notes
The notes give a clear chain:
- Rubin measured spiral galaxies’ rotation curves.
- She found outer stars orbit nearly as fast as inner stars.
- This conflicted with predictions based on visible matter alone.
- Her results provided evidence for dark matter.
- Her work led to broad acceptance of the dark matter hypothesis.
Check which option best synthesizes finding + impact
The strongest answer will combine (1) the specific surprising finding (uniform speeds) with (2) the scientific consequence (supporting dark matter and influencing acceptance). Choices that include only the finding, or only a general effect, are less effective.
Select the most effective synthesis
Rubin’s rotation-curve measurements revealed unexpectedly uniform stellar speeds, leading astronomers to embrace the idea of unseen dark matter.