Question 18·Hard·Central Ideas and Details
Historians have often credited the potato—with its extraordinary calorie yield per acre—for easing eighteenth-century Europe out of chronic food shortages. Yet recent economic studies reveal that in many regions the crop’s acreage expanded only after grain prices had stabilized and urban wages were already climbing. The researchers argue that while the potato’s productivity mattered, its decisive advantage was its adaptability to a market economy: the tuber could be stored for months, transported long distances with minimal loss, and processed into diverse products, making it an ideal hedge against price swings for both farmers and consumers.
Which choice best states the main idea of the text?
For main-idea questions, paraphrase the passage in 1–2 sentences, then identify the author’s emphasis by looking for contrast signals like “yet” and for phrases such as “the researchers argue” or “decisive advantage.” Eliminate choices that are too extreme, that focus on only the setup (the historians’ view) without the update (the new research), or that swap the passage’s main cause and secondary cause.
Hints
Focus on the contrast
The first sentence gives a common historical explanation; the next sentences beginning with “Yet” and “The researchers argue” indicate what the passage is really emphasizing.
Track what is ‘decisive’ vs. what merely ‘mattered’
One factor is described as important, but another is described as the decisive advantage. The main idea will highlight that distinction.
Avoid choices that go beyond the passage
Be cautious with answers claiming the potato played only a minor role or that the passage fully endorses the traditional explanation; the text is more nuanced.
Prefer the choice that combines both parts
The best answer should mention both (1) calorie yield helping with shortages and (2) market-economy advantages (storage/transport/versatility) driving adoption.
Step-by-step Explanation
Identify what the question is asking
The question asks for the main idea of the entire text. The correct choice should capture the passage’s overall claim, not just a single detail, and it should reflect the passage’s emphasis (especially where it contrasts views).
Summarize the passage
- Historians often credit the potato’s high calorie yield with easing chronic food shortages.
- Yet recent studies show potato acreage expanded only after grain prices stabilized and wages were rising.
- Researchers argue that while productivity mattered, the decisive advantage was market adaptability: it could be stored, transported, and processed, helping manage price swings.
Determine the passage’s emphasis
The passage does not reject the idea that the potato helped with shortages; it says productivity “mattered.” But it stresses that the main driver of widespread adoption was its usefulness in a developing market economy (storage, transport, versatility, hedging against price changes).
Choose the option that matches that emphasis
Eliminate choices that (1) claim the potato had little impact on shortages, (2) attribute adoption mainly to wages rather than the potato’s traits, or (3) treat calorie yield as the primary driver. The best main-idea choice is:
Although the potato’s high calorie yield helped mitigate famine, its ability to serve emerging market needs ultimately drove its widespread adoption in eighteenth-century Europe.