Question 223·Medium·Rhetorical Synthesis
While researching a topic, a student has taken the following notes:
- In 1930, astronomer Clyde Tombaugh discovered Pluto at Lowell Observatory.
- Pluto is much smaller than Earth.
- In 2006, the International Astronomical Union (IAU) reclassified Pluto as a dwarf planet.
- To be considered a planet, an object must clear other debris from its orbital path.
- Pluto shares its orbital zone with many Kuiper belt objects.
The student wants to explain why Pluto lost its status as a planet. Which choice most effectively uses relevant information from the notes to accomplish this goal?
For note-based rhetorical synthesis questions, start by underlining the task words in the question (such as 'why,' 'summarize,' or 'contrast') to be clear on the goal. Then quickly mark which notes are directly relevant to that goal—especially ones that show cause-and-effect if the question asks for a reason. When you read the answer choices, eliminate any that (1) use only background notes, not the key ones, (2) mention true details but don’t fulfill the stated goal, or (3) add information not supported by the notes. Choose the option that uses the necessary relevant notes and clearly achieves the specific purpose stated in the question.
Hints
Focus on the word "why"
The question asks for a sentence that explains why Pluto lost its planet status. Look for an answer that gives a cause-and-effect relationship, not just a description or a date.
Locate the rule and Pluto's problem in the notes
Among the notes, find the one that states the requirement for being a planet and the one that shows how Pluto does not meet that requirement. Those ideas are key to explaining the reason.
Connect the reason to the reclassification
Once you know the rule and how Pluto fails it, look for the answer choice that connects that failure to what the IAU did in 2006. The best choice should include both the reason and the resulting change in status.
Step-by-step Explanation
Identify the task: explain the reason (the "why")
The question says the student wants to explain why Pluto lost its status as a planet.
A good answer must therefore:
- Give the reason Pluto is not considered a planet (the cause), and
- Connect that reason to Pluto being reclassified (the effect).
Answers that only give background facts or only say that it was reclassified, without explaining why, will not be correct.
Find the notes that explain the reason
Scan the notes and ask: which ones actually explain why Pluto is no longer a planet?
Relevant notes for the reason:
- "To be considered a planet, an object must clear other debris from its orbital path." (This is the rule.)
- "Pluto shares its orbital zone with many Kuiper belt objects." (This shows Pluto does not meet the rule.)
A relevant note for the effect (what happened because of this):
- "In 2006, the International Astronomical Union (IAU) reclassified Pluto as a dwarf planet."
The best answer must connect the rule, Pluto’s situation, and the reclassification into one clear explanation.
Check which choices include both cause and effect
Now compare each answer choice to the key information you found:
- Does it mention the planet rule about clearing its orbit?
- Does it mention that Pluto doesn’t meet this rule because it shares its orbital zone with other objects?
- Does it connect this to the IAU’s 2006 reclassification as a dwarf planet?
Eliminate any choice that:
- Only mentions Pluto's size or discovery.
- Only states that it was reclassified without a reason.
- Only mentions that it shares its orbit, without tying that fact to the definition of a planet and the reclassification.
Select the choice that fully and directly answers the question
The correct answer must clearly say that Pluto failed the requirement to clear its orbit (because it shares its orbital zone with other Kuiper belt objects) and that this is why, in 2006, the IAU reclassified it as a dwarf planet.
Choice D does exactly this: "Because Pluto shares its orbital zone with other Kuiper belt objects and therefore has not cleared its orbit, the IAU reclassified it as a dwarf planet in 2006." This choice uses the notes accurately and directly explains why Pluto lost its status as a planet.