Drill 2 · Reading & Writing · Hard Command of Evidence
SAT Reading & Writing: Hard Command of Evidence (Drill 2) is a Reading & Writing practice drill covering Hard Command of Evidence. It contains 5 original questions created by Brian Stewart, a Barron's test prep author with over 20 years of tutoring experience.
Five hard Command of Evidence questions. Each one turns on what a piece of evidence has to do to fit a specific claim, not just on staying on topic. Three of the four choices are true or nearly true but fall short on scope, direction, or relationship. Two items ask you to read a graph or table closely.
Along a stretch of rocky coast, a species of marine snail grows a noticeably thicker shell in tide pools on the southern side of a headland than in pools on the northern side. The southern pools sit in direct sun for most of the day and are consistently several degrees warmer than the shaded northern pools. A marine biologist proposed that the warmer water itself drives the thicker shells, suggesting that the snails' shell-building chemistry works faster at higher temperatures. The biologist wanted to rule out the competing idea that the two sets of pools simply offer the snails different amounts of food.
Question 1. Which finding, if true, would most directly support the biologist's proposal?
Explanation: Choice C is the best answer because the proposal is that warmer water itself speeds shell building, so the evidence must isolate temperature from food. Snails moved to warmed tanks growing thicker shells than matched snails in cooler tanks with identical food holds food constant and varies only temperature, which is the exact mechanism proposed. Choice A is wrong because more algae in the southern pools supports the competing food explanation the biologist wants to rule out, not the temperature one. Choice B is wrong because a difference in body size says nothing about whether warmer water drives the thicker shells. Choice D is wrong because more shell-cracking crabs in the northern pools is about predation, a different cause than the temperature mechanism the proposal names.
A wastewater treatment plant began operating in 1985 and released its treated water into a lake just downstream. Researchers tracked dissolved phosphorus in that lake and in a nearby control lake with no plant upstream of it, measuring both every five years. They concluded that the plant, not some region-wide change, raised phosphorus in the downstream lake, reasoning that if a broad regional shift were responsible, both lakes would have changed together.
Question 2. Which choice best describes data from the graph that support the researchers' conclusion?
Explanation: Choice A is the best answer because the conclusion needs the downstream lake to change only after the plant opened while the control does not, which separates the plant from a region-wide shift. The graph shows the two lakes tracking each other near 12 to 15 until 1985, then the downstream lake climbing to about 52 by 2000 while the control holds flat, exactly that pattern. Choice B is wrong because the single highest point in 2000 is one endpoint and says nothing about the timing relative to 1985 that the conclusion turns on. Choice C is wrong because describing only the control lake never compares it to the downstream lake, so it cannot show the plant's effect. Choice D is wrong because it misreads the graph, since the two lakes were essentially equal before 1985 rather than the downstream lake being higher every year.
A coffee chain introduced a paid loyalty program and found that, on average, members spent considerably more per month at its stores than non-members did. The company concluded that the loyalty program causes members to spend more, proposing that the rewards give members a reason to choose its stores over competitors. Managers planned to expand the program on the strength of this conclusion.
Question 3. Which finding, if true, would most directly weaken the company's conclusion?
Explanation: Choice D is the best answer because the conclusion assumes the program raised members' spending, so a finding that the joiners were already the bigger spenders before any program existed shows the spending gap predates the program and may not be caused by it. Choice A is wrong because more frequent visits by members fits the company's conclusion and would tend to support it, not weaken it. Choice B is wrong because what competitors offer falls outside the comparison and tells us nothing about this program's effect on spending. Choice C is wrong because a preference for pricier seasonal drinks leaves open whether the program itself raised members' spending.
Detections of a Candidate Exoplanet by Four Surveys
| Survey | Method | Year | Status |
|---|---|---|---|
| Aurelia | Transit dip | 2009 | Confirmed |
| Borealis | Brightness flicker | 2007 | Unconfirmed |
| Caelum | Transit dip | 2012 | Confirmed |
| Doradus | Brightness flicker | 2005 | Unconfirmed |
An astronomer reviewing the record wanted to credit the earliest survey that produced a confirmed detection of the planet, treating the unconfirmed brightness-flicker reports as too uncertain to count. The astronomer concluded that the planet's earliest reliable detection was made by ________
Question 4. Which choice most effectively uses data from the table to complete the statement?
Explanation: Choice B is the best answer because the astronomer counts only confirmed detections, so the right cell is the earliest year among the confirmed rows. The two confirmed rows are Aurelia in 2009 and Caelum in 2012, and 2009 is the earlier, so Aurelia made the earliest reliable detection. Choice A is wrong because 2005 is the earliest year overall but it is an unconfirmed brightness-flicker report, which the astronomer excludes. Choice C is wrong because Caelum's 2012 detection is confirmed but it is the later of the two confirmed detections, not the earliest. Choice D is wrong because Borealis in 2007 is earlier than the confirmed detections but it is unconfirmed, so it does not count as reliable.
A city added a protected bike lane along a busy avenue and later counted far more cyclists on that avenue than before. Planners concluded that the protected lane brought new cyclists onto the road, arguing that the physical barrier made people who had been afraid to bike in traffic willing to start. A council member questioned whether the lane had created any new riders at all, rather than just pulling existing cyclists over from nearby streets.
Question 5. Which finding, if true, would most directly support the planners' conclusion?
Explanation: Choice C is the best answer because the conclusion is that the lane created new riders rather than relocating existing ones, so the evidence must show the riders are new. Most lane users reporting that they had not biked regularly anywhere before it opened directly establishes that the lane drew in people who were not already cycling. Choice A is wrong because steady counts on nearby side streets rule out only one source of existing riders, those streets, but do not show the lane users had not already been cycling elsewhere in the city, so it supports the planners less directly than the keyed choice. Choice B is wrong because when during the day the avenue is busiest is a side detail unrelated to whether the riders are new. Choice D is wrong because describing the curb restates a feature of the lane without showing it produced any new cyclists.