Central Ideas and Details questions ask for the main point of a short passage or for a specific detail it states.
Choices for a main-idea question often include one that is true but too narrow, covering a single example, and another that is too broad, claiming more than the passage supports. A passage describing a process that keeps changing from year to year, for instance, has a main idea about that change, not about any single step in it.
Detail questions reward going back to the text rather than relying on memory. The correct answer usually restates the passage in different words instead of repeating its phrasing.
Sample questions
Pick an answer to see whether it is right — nothing is saved, and nothing needs an account.
Question 1Easier
In 1915, chemist Alice Ball developed a method for turning oil from chaulmoogra seeds into a form that could be injected and absorbed by the body. The treatment brought relief to many people with Hansen’s disease and was used for years. Ball died at age twenty-four before publishing the method, and a colleague initially received much of the credit for it. Later researchers documented Ball’s role, and her achievement is now widely recognized.
Which choice best states the main idea of the text?
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Answer: B — Ball developed an important medical treatment but received proper credit for it only after her death.
The text focuses on Ball’s development of an effective treatment and explains that her contribution was credited properly only after her death.
Question 2Easier
A soil seed bank is sometimes described as a storehouse that preserves a fixed record of the plants growing above it. Long-term studies show a more dynamic system, however. Each year, some buried seeds germinate, others lose the ability to grow, and new seeds enter the soil. As a result, the species represented in a seed bank can change even when the plant community aboveground appears stable.
Which choice best states the main idea of the text?
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Answer: A — Soil seed banks are dynamic collections whose composition can change over time, even when aboveground vegetation seems stable.
The text explains that seeds continually enter, leave, and lose viability within a seed bank, so the bank changes over time rather than preserving a fixed record.
Question 3Easier
The following text is from Owen Brant’s 2019 article Ridges of Green.
Field biologist Mara Ellison spent three seasons mapping how alpine mosses survive on wind-scoured ridges in the Kestrel Range. Rather than spreading in continuous mats, the mosses formed small, widely spaced clumps that trapped windblown soil. Ellison measured higher moisture inside those clumps than on the bare rock between them. She concluded that the clumped pattern, though it leaves much of the ridge uncovered, is what lets the mosses persist through dry summers.
According to the text, what is true about Ellison?
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Answer: B — She found that clumped mosses held more moisture than the bare rock around them.
The text states that Ellison measured higher moisture inside the moss clumps than on the bare rock between them. The other choices contradict her methods or her conclusion: she worked for three seasons, described clumped rather than continuous growth, and argued that the clumps help the mosses persist through dry summers.
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