Reading & Writing · Information and Ideas
Command of Evidence: Textual
Explanation
Command of Evidence: Textual questions give you a short passage (most often describing a researcher’s hypothesis, a scholar’s claim, the conclusion of an experiment, or a specific feature of a literary work) and ask which piece of evidence would best serve a stated purpose. The most common prompts are “Which finding, if true, would most directly support the researchers’ hypothesis?”, “Which statement, if true, would most directly support (or weaken) the claim?”, “Which quotation from a researcher would best support the student’s assertion?”, and, for literary passages, “Which quotation from the text most effectively illustrates the claim?”
You are not asked whether a choice is factually real, only whether—assuming it is true—it logically strengthens or undermines the specific idea in the passage. The correct choice connects directly and completely to the exact claim; wrong choices are irrelevant, address a related but different point, point the opposite way, or merely call for more research. Success depends on pinning down precisely what must be supported before you weigh the four choices.
Example 1
The axolotl, a salamander that keeps juvenile features throughout its life, can regrow a lost limb with little or no scarring. Biologist Renata Vogel has proposed that this ability depends on the animal’s immune cells, called macrophages: she hypothesizes that macrophages clear cellular debris from a wound so quickly that the inflammation which normally produces scar tissue never fully develops.
Which finding, if true, would most directly support Vogel’s hypothesis?
A
Axolotls raised in captivity regenerate their limbs slightly more slowly than axolotls observed in the wild do.
B
When macrophages are experimentally removed from an axolotl’s wound, the wound heals with pronounced scar tissue and the limb fails to regenerate.
C
Axolotls possess a larger number of distinct immune cell types than most other salamander species do.
D
Several salamander species that cannot regenerate their limbs also have macrophages present in their wound tissue.
Choice B is the best answer because it presents a finding that, if true, would most directly support Vogel’s hypothesis that macrophages enable scar-free regeneration by clearing debris before scar-producing inflammation can develop. If removing macrophages causes the wound to scar and blocks regeneration, that result directly links the presence and activity of macrophages to the axolotl’s ability to regrow limbs without scarring, exactly as the hypothesis predicts. Choice A is incorrect because a small difference in regeneration speed between captive and wild axolotls says nothing about the role of macrophages in preventing scarring. Choice C is incorrect because the total number of immune cell types an axolotl has does not indicate whether macrophages specifically prevent scarring during regeneration. Choice D is incorrect because the mere presence of macrophages in salamanders that cannot regenerate would suggest that macrophages are not sufficient to explain scar-free regeneration, which would undermine rather than support the hypothesis.
Example 2
In her poem “Low Tide,” the poet Mara Ellison presents the sea as reluctant to give up the shore, describing the retreating water as if it were unwilling to leave. The poem reads in part, ______
Which quotation from “Low Tide” most effectively illustrates the claim?
A
“The gulls came down to walk the glistening flats / and pried the buried clams up one by one.”
B
“The water backed away with dragging steps / and clutched at every stone it had to leave.”
C
“By noon the sun had climbed above the cliffs / and warmed the pools the morning left behind.”
D
“Far out, a single fishing boat appeared, / its engine faint across the open bay.”
Choice B is the best answer because it most effectively illustrates the claim that the poem presents the retreating sea as reluctant to give up the shore. The quotation portrays the water backing away “with dragging steps” and “clutch[ing] at every stone it had to leave,” describing the tide as though it were unwilling to withdraw. Choice A is incorrect because it describes gulls feeding on the exposed flats, not the sea’s reluctance to retreat. Choice C is incorrect because it describes the midday sun and the tide pools, not the retreating water as unwilling to leave. Choice D is incorrect because it introduces a distant fishing boat and says nothing about the sea giving up the shore.
Tips for solving
- Before reading the choices, state in one sentence exactly what must be supported or weakened—the specific hypothesis, claim, or conclusion, not the general topic.
- Eliminate choices that point the wrong way. In a “support” item, a classic trap is a finding that would actually weaken the claim; in a “weaken” item, the trap points the other way.
Example: The claim states: "A new high-fiber diet plan improves digestion speed in healthy adults." (Question asks to SUPPORT the claim). The "Wrong Way" Trap Choice: "Participants on the high-fiber diet experienced an average 20% increase in food transit time through the digestive tract." Why it's a trap: Increasing transit time means digestion slowed down—this actually weakens the claim rather than supporting it.
- Watch for choices that are on-topic but off-claim—true, relevant-sounding details that address a different part of the passage or a question the claim never makes.
- Distrust choices that merely call for “more research,” restate the claim without adding evidence, or add a fact that has no logical bearing on the conclusion.
- In literary-illustration items, the correct quotation must contain every element of the claim (for example, both the thing described and the specific way it is described); a quotation that captures only part of the claim is wrong.
Example: The claim asserts that the protagonist feels both overwhelming awe and intense dread when viewing the ancient castle.
Incomplete Trap Choice (Captures awe only): "She gazed up at the towering, centuries-old spires, completely spellbound by the magnificent grandeur of the stone architecture."
Correct Choice (Captures both awe AND dread): "She gasped at the breath-taking majesty of the high stone towers, yet a chill of deep horror crept through her at the dark, looming shadows."
Practice questions
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Question 1 · easy
The Arctic ground squirrel survives winter by entering a state of torpor in which its body temperature drops below the freezing point of water, yet its blood does not freeze. Physiologist Daniel Reyes hypothesizes that the squirrel avoids freezing by lowering the concentration of tiny particles in its blood around which ice crystals would otherwise begin to form.
Which finding, if true, would most directly support Reyes’s hypothesis?
Question 2 · easy
Fireflies produce light through a chemical reaction in specialized cells in their abdomens. Researchers have long wondered why the flashes of one North American species are so precisely timed. Entomologist Lucia Marchetti proposes that the males of this species synchronize their flashes so that no single male’s signal stands out, forcing females to choose mates on the basis of flash brightness rather than timing.
Which finding, if true, would most directly support Marchetti’s proposal?
Question 3 · easy
The medieval city of Great Zimbabwe was built from granite blocks fitted together without mortar. A historian argues that the city’s builders were highly skilled stoneworkers whose techniques were passed down and refined over many generations, rather than developed hastily by a single group of workers.
Which finding, if true, would most directly support the historian’s argument?
Question 4 · easy
Some desert plants open the pores in their leaves only at night, taking in the carbon dioxide they need for photosynthesis after the sun has set. Botanist Ayaan Kapoor suggests that these plants open their pores at night rather than during the day in order to reduce the amount of water they lose to the dry desert air.
Which finding, if true, would most directly support Kapoor’s suggestion?
Question 5 · easy
The lionfish, a predator native to the Indo-Pacific, has spread rapidly through the Atlantic and Caribbean since the 1990s. A student writing a report on this spread asserts that the lionfish’s success in its new range is due in part to the local prey’s failure to recognize it as a threat.
Which quotation from a marine biologist would best support the student’s assertion?
Question 6 · easy
In his poem “The Ferryman,” the poet Oscar Neel describes an old boatman who has grown so familiar with the river that he no longer needs to look at the water to guide his craft across it. The poem reads in part, ______
Which quotation from “The Ferryman” most effectively illustrates the claim?
Question 7 · easy
To find out whether a certain songbird learns its song or is born already knowing it, researcher Nina Alvarez raised a group of the birds in isolation, where they never heard an adult of their species sing. Alvarez concluded that the birds must learn their song by listening to adults.
Which finding from the experiment, if true, would most directly support Alvarez’s conclusion?
Question 8 · easy
Honeybees returning to the hive perform a “waggle dance” whose angle and duration vary from bee to bee. A researcher claims that the dance communicates the direction and the distance of a food source to the other bees in the hive.
Which finding, if true, would most directly support the researcher’s claim?
Question 9 · easy
The wood frog can survive being frozen solid during the winter. Biologist Priya Sundar hypothesizes that the frog protects its cells from freezing damage by flooding them with glucose, a sugar that keeps the water inside the cells from forming the ice crystals that would otherwise destroy them.
Which finding, if true, would most directly support Sundar’s hypothesis?
Question 10 · easy
In her poem “Low Water,” the poet Mara Quinn presents the sun as a thief that steals the color from a summer field as the day wears on. The poem reads in part, ______
Which quotation from “Low Water” most effectively illustrates the claim?