9 original Central Ideas and Details questions, easiest first. The main idea of a passage, or a detail it actually states. Answer them all, then submit once to see every answer explained.
Volunteer-run seed libraries, which lend out seeds the way traditional libraries lend books, help preserve genetic diversity among regional plant varieties that commercial seed companies often no longer stock, a benefit frequently cited by advocates seeking municipal support for new seed library branches.
According to the text, why do advocates cite this genetic-diversity benefit?
A — To seek municipal support for new seed library branches.. The text states this benefit is 'frequently cited by advocates seeking municipal support for new seed library branches'—directly supporting choice A.
Venice was built on more than a hundred small islands in a lagoon, and its buildings rest on wooden pilings driven deep into the mud below; remarkably, many of these pilings, submerged and starved of oxygen for centuries, have effectively petrified rather than rotted.
According to the text, why have many of Venice's wooden pilings survived for centuries rather than rotting?
C — They are submerged and lack the oxygen that would otherwise cause them to decay.. The text says the pilings, 'submerged and starved of oxygen,' have 'effectively petrified rather than rotted'—directly supporting choice C; the other options contradict or are unsupported by the text.
A recent survey of hiring managers found that the most commonly cited reason for rejecting a job candidate was not a lack of relevant experience, as many job seekers assume, but poor communication during the interview itself.
According to the text, what did the survey identify as the most common reason for rejecting a candidate?
B — Poor communication during the interview.. The text explicitly states the most common reason was 'poor communication during the interview itself,' explicitly ruling out lack of experience as the assumed but incorrect answer.
A recent survey of apartment renters found that the most commonly cited reason for choosing not to renew a lease was not rising rent, as many landlords assume, but unresolved maintenance requests that went unaddressed for weeks at a time.
According to the text, what did the survey identify as the most common reason renters chose not to renew?
D — Unresolved maintenance requests.. The text explicitly states the most common reason was 'unresolved maintenance requests that went unaddressed for weeks at a time,' explicitly ruling out rising rent as the assumed but incorrect answer.
Octopuses possess a remarkable form of distributed intelligence: roughly two-thirds of their neurons are located not in the brain but in their arms. Each arm can taste, touch, and even make certain decisions on its own, letting the animal probe several crevices at once without central direction.
Which choice best states the main idea of the text?
A — Much of an octopus's cognition is distributed throughout its arms.. The passage's central claim is that intelligence is 'distributed'—most neurons and some decision-making sit in the arms. A states this; B contradicts it, and C and D are minor details, not the main idea.
Certain species of spider practice a form of chemical camouflage, coating their bodies in scent compounds that mimic the pheromones of the ants they live among; this disguise allows the spiders to move freely through ant colonies without triggering the ants' usual aggressive defenses.
According to the text, how does the chemical camouflage benefit the spider?
C — It allows the spider to move through ant colonies without triggering aggressive defenses.. The text directly states the disguise 'allows the spiders to move freely through ant colonies without triggering the ants' usual aggressive defenses'—this is stated explicitly, unlike the other unsupported options.
Wolves are considered a keystone species in some ecosystems because their presence alters the grazing behavior of deer and elk, which in turn allows young trees along riverbanks to grow undisturbed, stabilizing soil and supporting a wider range of other wildlife.
According to the text, why are wolves considered a keystone species in some ecosystems?
D — Their presence alters grazing behavior in ways that ultimately support a wider range of wildlife.. The text directly states wolves are keystone species 'because their presence alters the grazing behavior of deer and elk,' which ultimately 'supports a wider range of other wildlife'—matching choice D explicitly.
Honeybees communicate the location of food sources to their hive-mates through a series of movements known as the waggle dance, in which the angle and duration of the dance correspond to the direction and distance of the food relative to the sun.
According to the text, what do the angle and duration of the waggle dance indicate?
A — The direction and distance of a food source.. The text directly states the angle and duration 'correspond to the direction and distance of the food'—this is stated explicitly, unlike the other unsupported options.
Redwood trees, among the tallest living organisms on Earth, draw much of their water not from their roots alone but by directly absorbing moisture from coastal fog through microscopic pores in their needles, a process especially important during California's dry summer months.
According to the text, how do redwood trees obtain water beyond what their roots provide?
B — By absorbing moisture from coastal fog through pores in their needles.. The text directly states redwoods obtain water 'by directly absorbing moisture from coastal fog through microscopic pores in their needles'—matching choice B; the other options contradict or are unsupported by the text.
Score:
Every question above is now marked up: the correct answer is highlighted, any wrong option you picked is flagged, and each explanation is open.
No. Every question here is original, written to the College Board's published Digital SAT Reading & Writing specification for the Central Ideas and Details skill. No retired or copyrighted College Board material appears anywhere on this site.
Central Ideas and Details asks either for the main idea of a short passage or for a specific detail the passage states. Both are answered entirely from the text — nothing is inferred, nothing is brought in from outside — but the main-idea version requires the choice to cover the whole passage rather than one part of it.
For a main-idea question, summarise the passage in one sentence before looking at the choices, then eliminate any choice that is true of only one sentence. For a detail question, find the exact line the question points at and match against it word by word — the correct choice paraphrases it, but it never adds to it.
No, and deliberately so. This drill is 9 Central Ideas and Details questions back to back; a real Reading & Writing module is 27 questions in 32 minutes drawn from all eleven skills. Use a drill to fix one weakness, then take a full module to practice the real thing.
No. The SAT has no penalty for a wrong answer — a blank and a wrong guess both score zero — so answer every question, including the ones you have to guess.