All practice questions

Read the passage below:

"The submersible, Alvin, sank through the twilight zone, its exterior headlights casting a dim cone of light into the abyss. To the crew monitoring the descent from the surface ship, the vessel was merely a blinking green icon on a telemetry screen. But inside the cramped steel sphere, Dr. Aris felt the walls pressing inward, his own breath loud and ragged against the hum of the oxygen scrubbers. *Why did I agree to this depth?* he wondered, staring at the empty black water beyond the quartz viewport. For decades, marine biologists had assumed that the abyssal plains were barren deserts, devoid of life and energy. They wrote textbooks detailing a static, silent world. Yet, as the submersible touched the seafloor, a sudden burst of bioluminescence erupted from the silt—a shimmering field of glass sponges that defied every established theory of deep-sea ecology."

Based on the passage, arrange the following narrative perspectives in the order in which they appear, from first to last.

To investigate how salinity affects the heart rate of *Daphnia magna* (water fleas), a researcher prepared $4$ beakers containing different water solutions. Beaker $1$ contained pond water with $0\%$ added salt. Beaker $2$ contained pond water with $0.5\%$ added salt. Beaker $3$ contained pond water with $1.0\%$ added salt. Beaker $4$ contained pond water with $1.5\%$ added salt. In each beaker, $10$ *Daphnia magna* were placed, and their average heart rate was recorded after $30$ minutes. Which beaker serves as the control group to establish the baseline heart rate under normal conditions?

Passage A

The rise of citizen science—projects in which volunteers partner with professional scientists to collect and analyze data—represents a profound democratization of scientific inquiry. Historically, scientific research was locked behind the gates of academia, constrained by limited budgets and small field teams. Today, projects like the Audubon Society’s Christmas Bird Count or global water quality monitoring initiatives enlist hundreds of thousands of ordinary citizens. This collective effort generates massive, continental-scale datasets that would be impossible for traditional research teams to acquire due to funding and labor constraints. More importantly, citizen science bridges the chasm between the scientific community and the general public. By actively participating in the scientific method, volunteers develop scientific literacy and a sense of shared ownership over local conservation efforts. This active engagement fosters public trust in scientific findings at a time when skepticism of authority is high. Citizen science is not merely a tool for data collection; it is a collaborative movement that empowers communities and transforms science from an insular pursuit into a shared public endeavor.

Passage B

While the enthusiasm surrounding citizen science is understandable, the scientific community must approach the integration of amateur-collected data with rigorous skepticism. The primary concern is data quality. Unlike trained researchers who adhere to strict, standardized protocols, volunteers have varying levels of expertise and commitment. This variability introduces significant noise and systematic bias into datasets, such as the overreporting of charismatic species or data collection concentrated solely near accessible urban roads. When federal agencies or local governments base conservation policies on these flawed datasets, they risk misallocating scarce resources. Furthermore, the promotion of citizen science as a cost-effective substitute for professional research threatens to undermine funding for traditional science. Enlisting unpaid volunteers should not justify the reduction of budgets for professional field biologists, whose expertise is critical for nuanced ecological analysis. To maintain scientific integrity, citizen science should be relegated to a supplementary educational tool rather than a primary method of empirical investigation, ensuring that policy remains guided by professional expertise.

Which of the following statements best describes the difference in how the authors of Passage A and Passage B view the primary value of citizen science?

The following passage explores the debate surrounding the 'Early Anthropocene Hypothesis.'

For decades, the consensus among geologists and climatologists was that human activity began to alter the global climate only with the advent of the Industrial Revolution in the late eighteenth century. According to this traditional view, the burning of fossil fuels and large-scale manufacturing marked the definitive boundary of the Anthropocene. However, in $2003$, climatologist William Ruddiman proposed the controversial 'Early Anthropocene Hypothesis,' shifting this timeline back by thousands of years. Ruddiman argued that early agricultural practices initiated a slow, sustained warming trend that prevented the onset of a scheduled glacial period.

To construct his argument, Ruddiman first analyzed ice core data from Antarctica, which records historical levels of greenhouse gases. Over the past several hundred thousand years, carbon dioxide ($CO_2$) and methane ($CH_4$) levels consistently peaked during warm interglacial periods and then gradually declined due to predictable variations in Earth's orbit. Yet, Ruddiman noticed a distinct departure from this natural pattern: approximately $8{}000$ years ago, atmospheric $CO_2$ levels unexpectedly began to rise, followed by a similar upward trajectory in $CH_4$ levels around $5{}000$ years ago.

Having identified these anomalies, Ruddiman sought to establish a causal link to human action. He proposed that the rising $CO_2$ resulted from massive deforestation as early European farmers cleared land for agriculture. The subsequent rise in $CH_4$ was attributed to the expansion of wet-rice cultivation in Southeast Asia, which created artificial wetlands that released large volumes of the gas.

Critics of the hypothesis argued that early human populations were too small to generate such global effects, suggesting instead that natural changes in ocean circulation and solar output drove the warming. In response, Ruddiman and his supporters refined their models, demonstrating that early agricultural techniques were highly inefficient, requiring far more land per person than modern farming. By showing that a small population could cause disproportionately high deforestation, Ruddiman successfully defended the chronological progression of his argument, establishing a new framework for understanding human-environmental history.

Based on the passage, arrange the following steps in the development and defense of William Ruddiman’s Early Anthropocene Hypothesis in their logical chronological order, from the initial scientific observations to the final counter-defense.

For decades, paleontologists have debated the primary driver behind the sudden extinction of North America's Pleistocene megafauna, such as mammoths and saber-toothed cats, around 13,000 years ago. The 'overkill hypothesis' posits that newly arrived human hunters, possessing advanced Clovis projectile points, hunted these large mammals to extinction within a few centuries. Proponents of this model point to the chronological coincidence between the arrival of humans and the disappearance of the megafauna.

However, critics argue that the archaeological record does not sufficiently support this scenario. Opponents emphasize that of the dozens of megafaunal species that went extinct, only a tiny fraction—namely mammoths and mastodons—have been found in direct association with Clovis hunting tools at archaeological sites. Furthermore, they note that several large species, such as bison, survived the period despite being hunted by humans. Critics suggest that rapid climate fluctuations at the end of the Pleistocene epoch, which dramatically altered habitats and food webs, were the actual primary driver of the extinctions, rather than human overhunting.

According to the passage, critics point to the low number of extinct megafaunal species found alongside Clovis tools in order to support which of the following claims?

Read the passage below:

For over three centuries, the astronomical clock of the Old Town Hall had served as the mechanical heartbeat of the city. Scholars of medieval engineering often marvel at the intricate coordination of its dial wheels, which tracked not only the hour but also the positions of the sun and moon against the zodiac. To the modern observer, the clock represents a triumph of communal effort, a public monument designed to make the cosmic order visible to the average citizen.

But as Caleb adjusted the escapement on that chilly November evening in 1704, the grand symbolism of the town square receded. His world contracted to the microscopic friction between brass teeth and steel pallets. He did not think of cosmic harmony; he thought of his daughter’s failing health and the single gold coin the city council had promised upon the project's completion. Each swing of the pendulum was not a measurement of celestial motion, but a countdown of the precious hours he had left to save her.

The shift in point of view from the first paragraph to the second paragraph can best be described as a transition from:

Passage A

The transition toward a cashless society is not merely a convenience of modern banking; it is a vital step toward a more transparent and efficient economy. Paper currency is anonymous, bulky, and expensive to print, secure, and transport. By replacing physical banknotes with digital transactions, societies can drastically reduce cash-associated crimes, such as tax evasion, money laundering, and counterfeiting. Every digital transaction leaves a traceable electronic footprint, making it far more difficult for illicit financial networks to operate undetected. Furthermore, digital payment systems lower transaction costs for small businesses, streamline accounting, and facilitate seamless international commerce. While critics raise concerns about surveillance, the regulatory framework can be designed to protect consumer privacy while preserving the benefits of traceability. Ultimately, cash is an analog relic in a digital world, and transitioning away from it will enable governments to better manage monetary policy, stabilize financial systems, and ensure that the modern economy operates with maximum integrity and efficiency.

Passage B

The enthusiastic push to eliminate physical currency overlooks a fundamental truth: cash is a cornerstone of economic liberty and financial inclusion. Unlike digital payment networks, cash requires no electricity, no internet connection, and no relationship with a private banking institution. For the millions of "unbanked" individuals worldwide—particularly low-income citizens, elderly populations, and undocumented immigrants—cash is the only accessible means of participating in the economy. Forcing a transition to digital-only transactions effectively disenfranchises these vulnerable groups. Moreover, cash provides absolute privacy, serving as a vital shield against corporate surveillance and state overreach. When every transaction is recorded, financial institutions and governments gain unprecedented access to citizens' private lives, creating potential for abuse. Finally, a cashless system introduces severe systemic vulnerability. A single cyberattack, power grid failure, or banking glitch can freeze an entire economy instantly. Cash acts as a crucial fail-safe. Relinquishing it for the sake of corporate convenience is a dangerous exchange of freedom and security for mere efficiency.

Based on the passages, which of the following best describes the difference in how the two authors view the role of tracking or tracing transactions in a cashless society?

The following passage is adapted from a scientific essay on evolutionary biology.

For over a century, evolutionary biologists debated the adaptive function of the zebra's distinctive black-and-white stripes. The classic hypothesis, famously championed by nineteenth-century naturalists, proposed that stripes functioned as a form of camouflage. By blending into the shimmering heat waves and tall grasses of the African savannah, zebras were thought to confuse predators like lions. However, this theory struggled under closer scrutiny; lions are visual hunters, but they primarily detect prey by movement and scent rather than static visual patterns. Furthermore, zebras are noisy and social animals, making quiet concealment highly unlikely, as they rarely attempt to hide from predators.

To address these shortcomings, researchers in the mid-twentieth century proposed an alternative explanation: the stripes served a social function, facilitating group cohesion or individual recognition within herds. While plausible, this hypothesis lacked empirical support. Zebras indeed exhibit complex social behaviors, but other closely related equids (such as wild asses) show similar herd dynamics without requiring high-contrast markings. Consequently, the social cohesion theory remained largely speculative, failing to explain why zebras specifically evolved such unique coats.

A significant breakthrough came when researchers began investigating the sensory systems of blood-sucking insects rather than large carnivores. In a series of controlled experiments, scientists discovered that tabanids (biting flies) are highly sensitive to polarized light. Biting flies use polarized light reflections from dark animal hides to locate hosts. High-contrast striped patterns disrupt this light reflection, creating an optical illusion that makes it difficult for flies to land successfully. Comparative studies across equid species soon confirmed that striping patterns correlate strongly with regions of high biting-fly activity, providing a robust ecological explanation for the trait. By sequencing their evidence from predator-avoidance failures to physical insect-landing experiments, scientists shifted the paradigm of zebra stripe research.

In the context of the passage's argument, the author's discussion of wild asses and other unstriped equids functions primarily to do which of the following?

Passage

Biologists observing Australian bushfires have long noted that raptors, such as the black kite (*Milvus migrans*) and brown falcon (*Falco berigora*), congregate at fire fronts to capture escaping prey. However, a study by Bonta et al. proposes a far more active role: these birds act as 'pyrophiles' that intentionally propagate fire by carrying burning twigs in their talons to unburned areas. Skeptics argue that this behavior is accidental, suggesting that birds merely drop embers while retrieving prey. To evaluate these competing interpretations, researchers analyzed three key behavioral patterns: first, multiple birds systematically carrying embers to the same unburned patch; second, the selection of smoldering hardwood twigs over lighter, fast-burning grass; and third, the directional movement of birds against prevailing winds to start new fire lines, maximizing prey exposure. These observations suggest a deliberate ecological strategy rather than sporadic, accidental occurrences. By starting new fires, the raptors force prey out of previously safe havens, suggesting that the behavior is a coordinated hunting tactic.

Question

Based on the passage, match each of the researchers' claims about raptor behavior on the left with the specific evidence that supports it on the right.

A student conducted three experiments to investigate how a new liquid fertilizer affects the stem growth of a certain plant species under various environmental conditions. In each experiment, the plants were grown in identical pots with standard soil:

* Experiment 1 was conducted in a low-light environment ($500\text{ lux}$).
* Experiment 2 was conducted in a high-light environment ($2{}000\text{ lux}$).
* Experiment 3 was conducted in a high-temperature chamber ($30^\circ\text{C}$).

To determine if the liquid fertilizer is effective, the student must compare the fertilizer-treated plants to the correct control groups. Match each experimental setup with the correct control group configuration required to isolate the fertilizer's effect.

The following passage explores the scientific debate surrounding the origins of Earth's water.

For decades, planetary scientists widely accepted the 'late veneer' hypothesis to explain the origin of Earth’s oceans. According to this model, early Earth was entirely dry due to the high-temperature conditions of the inner solar nebula, which would have vaporized any volatile compounds. Water, therefore, must have been delivered to the surface after the planet had fully accreted and cooled, presumably during the Late Heavy Bombardment around $3.9$ billion years ago. The primary candidates for this delivery were comets—icy remnants of the early solar system originating from the outer reaches, where water could easily freeze and accumulate.

However, this comet-delivery model faced a critical setback with the advent of direct space-probe measurements. In $1986$, the Giotto mission measured the deuterium-to-hydrogen ($D/H$) ratio in the water of Halley's Comet. Scientists discovered that Halley’s water had a $D/H$ ratio roughly twice that of Earth’s oceans. Subsequent missions to other comets, including the Rosetta mission to Comet 67P in $2014$, confirmed this discrepancy: comet water is isotopically heavier than terrestrial water. Because the isotopic signature of water does not change over geological time, comets could not have been the primary source of Earth’s oceans.

This geochemical mismatch prompted a reevaluation of carbonaceous chondrite meteorites as the true carriers of terrestrial water. Originating from the outer asteroid belt, these meteorites contain water bound in hydrated clay minerals. Isotopic analyses of carbonaceous chondrites revealed that their $D/H$ ratios match Earth’s ocean water almost perfectly. This suggested that water delivery occurred earlier than previously thought, during the main phase of Earth’s accretion, rather than as a late addition.

This chondritic origin has been further reinforced by recent analyses of deep mantle rocks. Geochemists studying volcanic glass from Baffin Island discovered hydrogen isotopic signatures in Earth's deep mantle that are even lower than those of chondrites. This evidence suggests that a significant portion of Earth's water was present in the dust cloud from which the planet formed, trapped within the Earth since its accretion. Thus, the narrative has shifted from late cometary bombardment to early, endogenous water accumulation.

Based on the passage, arrange the phases of the scientific debate regarding the origin of Earth's water in the order they are presented, tracing the progression from the initial hypothesis to the most recent findings.

Read the passage below:

I clutched the leather-bound promptbook, my knuckles white under the dim blue worklights of the wings. For six grueling months, this drafty stage had been my battleground, a place where I fought every afternoon to coax a masterpiece from a reluctant cast. Now, as the gold velvet curtain slowly parted, I was reduced to a silent ghost in the shadows, entirely helpless to intervene.

On stage, Clara stood frozen in the center spotlight, shivering despite the intense heat radiating from the lamps. She felt the heavy velvet of her costume pressing against her collarbone like lead, her mind racing as she wondered if she would remember the opening line that had completely eluded her during yesterday's dress rehearsal. Her fingers trembled against her skirt.

Below them, in the cavernous darkness of the auditorium, five hundred spectators held their breath in unison. None of them were aware of the fraying rope above the proscenium arch, nor could they sense the director’s quiet panic in the wings. They were simply a single, collective entity, waiting with suspended judgment to be transported to another world.

Based on the passage, match each excerpt with the specific narrative point of view it represents.

A student designs an experiment to test how different concentrations of salt water affect the germination rate of radish seeds. The student places 50 radish seeds in each of four petri dishes. Each dish is watered with a different concentration of salt solution ($0\%$, $1\%$, $2\%$, and $3\%$ salt). All petri dishes are kept in the same incubator at a constant temperature of $22^\circ\text{C}$ and receive 12 hours of light daily. After 5 days, the student counts the total number of germinated seeds in each dish. Match each experimental component on the left with its correct variable classification on the right.

To study the effectiveness of a new liquid antimicrobial agent, Agent Y, researchers performed an experiment using agar plates inoculated with *Escherichia coli*. Four plates were prepared under identical conditions:

* Plate 1: Treated with $5\text{ mL}$ of a $20\%$ Agent Y solution dissolved in distilled water.
* Plate 2: Treated with $5\text{ mL}$ of a $10\%$ Agent Y solution dissolved in distilled water.
* Plate 3: Treated with $5\text{ mL}$ of a $5\%$ Agent Y solution dissolved in distilled water.
* Plate 4: Treated with $5\text{ mL}$ of pure distilled water.

All plates were incubated at $37^\circ\text{C}$ for $24\text{ hours}$. Afterward, the diameter of the zone of inhibition (the clear area where bacterial growth was prevented) was measured in millimeters ($\text{mm}$).

Which of the plates serves as the control group to determine the baseline bacterial growth in the absence of the antimicrobial Agent Y?

Passage

For years, cognitive scientists widely accepted the 'bilingual advantage' hypothesis, which posits that managing two languages enhances executive function, such as working memory and cognitive flexibility. This claim was supported by early, small-scale studies showing bilinguals outperforming monolinguals on tasks like the Simon sorting game. However, researcher Dr. Elena Vance recently conducted a meta-analysis of over one hundred studies on bilingual cognition. Vance’s analysis revealed a striking pattern: while small studies with fewer than fifty participants frequently reported a significant bilingual advantage, larger studies with sample sizes exceeding three hundred consistently showed no statistically significant difference in executive function between the two groups. Vance argues that this discrepancy is evidence of publication bias, where studies showing positive results are disproportionately published, while those showing null results are shelved. To support this, she demonstrated that the average effect size decreased systematically as the sample size of the studies increased. Vance contends that once this bias is statistically corrected, the cognitive advantage of bilingualism effectively vanishes.

According to the passage, which of the following findings does Dr. Vance present as direct support for her claim that publication bias has distorted the research on the 'bilingual advantage'?

Passage A
The night sky has long been a shared human heritage, inspiring science, philosophy, and art. However, the rapid proliferation of low-Earth orbit (LEO) satellite constellations threatens to obscure this view forever. For astronomers, these satellites leave bright streaks across telescope images, ruining years of sensitive cosmic research. The loss is not merely professional; it is existential. By wrapping the planet in an artificial web of light, we are severing our connection to the cosmos. Proponents of these mega-constellations argue they are necessary for global connectivity, but they ignore the irreversible damage done to our environment. The night sky is an ecological wilderness that deserves protection just as much as our oceans or national parks. Once we fill our orbit with thousands of reflective orbital objects, the pristine darkness that guided humanity for millennia will be lost, replaced by a flashing grid of corporate infrastructure. We must halt further launches until international regulations can preserve the astronomical commons.

Passage B
Access to high-speed internet is no longer a luxury; it is a fundamental driver of economic mobility, education, and healthcare. Yet, billions of people in rural and remote regions remain cut off from the digital world because traditional ground-based infrastructure is too costly or geographically impossible to build. Low-Earth orbit satellite constellations offer a revolutionary solution, bridging the digital divide and democratizing access to information. While some astronomers argue that these satellites interfere with cosmic observations, satellite operators are actively working to reduce reflectivity and coordinate orbit pathways to minimize interference. The concerns of the scientific community, though valid, must be balanced against the immediate human benefit of lifting entire communities out of economic isolation. A dark sky is indeed beautiful, but the progress of global equity is far more urgent. Rather than halting progress, we must foster collaboration between technologists and researchers to ensure that connectivity does not come at the cost of discovery.

Which of the following statements best describes a key difference in how the authors of Passage A and Passage B view the development of low-Earth orbit satellite constellations?

A researcher investigated the effect of different concentrations of glucose on the fermentation rate of yeast (*Saccharomyces cerevisiae*). Five test tubes were prepared, each containing $10\text{ mL}$ of a yeast suspension and a specific concentration of glucose dissolved in distilled water. The tubes were maintained at $30^\circ\text{C}$ for $30$ minutes. The volume of carbon dioxide ($\text{CO}_2$) gas produced in each tube was measured to determine the rate of fermentation. The experimental setups are shown in the table below:

Which of the following tubes served as the control group to establish the baseline level of gas production in the absence of glucose?

A student conducted an experiment to determine how the temperature of a reactant solution affects the rate of a chemical reaction. The student placed equal volumes of $1.0\text{ M}$ hydrochloric acid ($\text{HCl}$) in five identical beakers. Each beaker was maintained at a different temperature ($10^\circ\text{C}$, $20^\circ\text{C}$, $30^\circ\text{C}$, $40^\circ\text{C}$, or $50^\circ\text{C}$). The student then added a $1.0\text{ g}$ strip of magnesium ribbon to each beaker and recorded the time it took for the magnesium ribbon to completely dissolve. Based on this description, which of the following was the independent variable in the experiment?

A group of students designed an experiment to investigate the factors that influence the corrosion (rusting) of iron. Identical iron nails were placed in 5 different test tubes under the conditions described below:

* Tube 1: Nail fully submerged in $10\text{ mL}$ of distilled water, with a layer of mineral oil on top to prevent contact with atmospheric oxygen.
* Tube 2: Nail exposed to ambient air only (no liquid).
* Tube 3: Nail fully submerged in $10\text{ mL}$ of distilled water exposed to ambient air.
* Tube 4: Nail fully submerged in $10\text{ mL}$ of a $3\%\text{ NaCl}$ (salt) solution exposed to ambient air.
* Tube 5: Nail fully submerged in $10\text{ mL}$ of a $5\%$ acetic acid (vinegar) solution exposed to ambient air.

Match each test tube to its specific role in the experimental design.

Two students discuss the source of water on Earth.

Student 1
Earth's water came entirely from icy comets that bombarded the planet during its early history. Comets are composed largely of water ice, and as they collided with the young, hot Earth, the ice melted, vaporized, and eventually condensed to form the oceans. This explains why the ratio of deuterium (a heavy isotope of hydrogen) to normal hydrogen in Earth's oceans matches the ratio found in comets in the outer solar system.

Student 2
Earth's water did not come from comets, but rather from within the Earth itself. During the planet's formation, water was trapped inside rocks in the mantle. Volcanic eruptions released this water as vapor into the early atmosphere, which then cooled and fell as rain to form the oceans. The deuterium-to-hydrogen ratio in the oceans matches that of mineral-bound water found in ancient meteorites, which were the building blocks of early Earth, not comets.

Based on the passage, Student 1's explanation of the origin of Earth's water relies on which of the following assumptions?