Information and Ideas

The Martian meteorite Northwest Africa (NWA) 7034, nicknamed "Black Beauty," contains significantly more water than most other Martian meteorites. In a study, planetary scientist Dr. Ananya Sen and her team analyzed the meteorite's clasts, which are fragments of older rocks cemented together. The researchers determined that the water is primarily locked within apatite crystals inside the basaltic clasts, rather than in the surrounding impact-melt matrix or as a result of terrestrial contamination. Furthermore, the team found that the isotopic signature of the hydrogen in this mineral-bound water matches the Martian atmospheric composition from approximately 4.4 billion years ago, rather than the contemporary Martian atmosphere or terrestrial reservoirs.

Based on the text, what is true of the water found in the Northwest Africa (NWA) 7034 meteorite?

To defend against herbivorous insects, certain tobacco plants produce nicotine, a potent neurotoxin. However, synthesizing nicotine is metabolically costly, requiring nitrogen that would otherwise support leaf growth. Researchers observed that when tobacco plants are exposed to volatile organic compounds (VOCs) released by neighboring plants already under attack, they do not immediately increase nicotine production. Instead, their roots initiate transcription of genes associated with nicotine synthesis, leaving the actual production pathway inactive until direct herbivore damage occurs. Which choice most logically completes the text?

For years, cognitive psychologists championed the 'bilingual advantage' hypothesis, which posits that managing two languages enhances general executive functioning, such as working memory and cognitive flexibility. However, recent large-scale replication studies have challenged this broad claim, finding negligible differences in general cognitive tests between bilinguals and monolinguals. Instead of demonstrating a global executive boost, current research suggests that bilingualism's cognitive effects are highly task-specific, primarily improving performance on tasks that directly mimic the linguistic switching and monitoring required in daily bilingual communication. Thus, the cognitive impact of bilingualism is best understood not as a systemic enhancement of the brain's processing power, but as a specialized adaptation to specific communicative demands.

Which choice best states the main idea of the text?

Many plants form symbiotic relationships with mycorrhizal fungi, which supply the plants with soil nutrients in exchange for carbon. While both arbuscular mycorrhizal (AM) fungi and ectomycorrhizal (ECM) fungi assist in nutrient uptake, they differ in how they impact soil carbon storage. AM fungi release glomalin, a glycoprotein that binds soil particles together and slows carbon decomposition. In contrast, ECM fungi produce enzymes that actively break down organic matter to access nitrogen ($N$), a process that releases carbon dioxide ($CO_2$) back into the atmosphere. Which choice most logically completes the text?

Ecologist Dr. Clara Mercer studied the nesting habits of Eastern Gray Squirrels (*Sciurus carolinensis*) in different environments. Mercer claimed that squirrels nesting in busy urban parks, which have high levels of human foot traffic, build their nests much higher up in trees than squirrels nesting in quiet suburban areas do, in order to stay safe from ground-level disturbances. Which choice, if true, would most directly support Mercer's claim?

The Aztecs developed an innovative agricultural method known as *chinampas*, or 'floating gardens,' to cultivate crops in the shallow lakebeds of the Valley of Mexico. To construct a chinampa, farmers wove rectangular frames from branches and reeds, anchored them to the lakebed with willow trees, and filled the enclosures with decaying vegetation and nutrient-rich lake mud. This design allowed water to continuously irrigate the roots of the crops from below, eliminating the need for manual watering. Consequently, chinampas could support multiple harvests per year, sustaining the growing population of the Aztec capital, Tenochtitlan.

Based on the text, which statement is true about the irrigation of crops grown on chinampas?

Literary scholar Dr. Liam Sterling analyzed stylistic markers in the correspondence networks of nineteenth-century British authors. Sterling hypothesized that authors who coauthored novels or essays with peers would show a marked, long-term increase in stylistic similarity in their private letters specifically to those collaborators, rather than experiencing a generalized shift in style that affected their correspondence with other contemporaries.

Which finding, if true, would most directly support Sterling's hypothesis?

Archaeologists studying ancient textiles often struggle to recover organic fibers, which decay rapidly in typical soil conditions. However, when silk is buried in close proximity to bronze or copper artifacts, a process known as mineralization can occur. Soluble metal ions from the corroding artifacts gradually infiltrate the organic fibers, replacing the protein structure with durable metal salts while preserving the textile's fine microstructural details. Consequently, these metallic pseudomorphs allow researchers to study weave patterns and textile technologies from eras whose organic remains have otherwise completely vanished.

Which choice best states the main idea of the text?

Musicologist Dr. Kenji Sato investigated the impact of early radio broadcasts on regional folk music (*min'yo*) in Japan during the 1920s. Some historians argue that the rise of national broadcasting led to the homogenization of Japanese musical culture, erasing local variations. Sato, however, contends that radio broadcasts actually revitalized distinct regional traditions by elevating the prestige of local performers and encouraging young musicians in remote provinces to preserve their unique musical heritages. Which choice, if true, would most directly support Sato's contention?

Linguist Dr. Marcus Chen studied the adoption of foreign words in coastal trading communities. Chen claims that merchants in these communities borrow foreign words primarily to describe navigation instruments rather than trade goods. Which choice, if true, most directly supports Chen's claim?

Though taxonomically classified alongside active predators, the deep-sea cephalopod *Vampyroteuthis infernalis* (the vampire squid) employs a passive detrital feeding strategy unique among its relatives. Inhabiting the ocean's oxygen minimum zone—a region of extreme hypoxia—the species cannot sustain the metabolic demands of active hunting. Instead, it deploys two long, retractile sensory filaments to capture falling marine snow, which comprises sinking organic debris such as fecal pellets and planktonic remains. Once these particulates accumulate on the sticky filaments, the squid retracts them, utilizing its arms' specialized, finger-like projections called cirri to scrape the collected debris from the filaments and transfer it to its mouth. This low-energy dietary adaptation allows the organism to occupy a physiological niche that excludes typical marine predators.

Based on the text, what is true of the cirri of *Vampyroteuthis infernalis*?

Microorganisms in deep terrestrial aquifers subsist under extreme energy limitation, often taking centuries to divide. Scientists debate whether these microbes maintain active cellular repair mechanisms or merely persist in a dormant state of gradual decay. To investigate, researchers analyzed intracellular proteins from microbes collected two kilometers below Earth’s surface. They focused on amino acid racemization, a spontaneous process that converts biological L-amino acids into D-amino acids, which cells must expend energy to repair. The team found that the ratio of D- to L-amino acids in the proteins was significantly lower than expected from spontaneous chemical decay over the geological age of the aquifer, suggesting that ______

Which choice most logically completes the text?

The thorny devil (*Moloch horridus*), a lizard native to the arid regions of Australia, has evolved a specialized method for gathering water in its desert habitat. Rather than drinking directly through its mouth, the lizard utilizes a network of microscopic grooves located between its scales. When dew or rain contacts the lizard's skin, capillary action draws the liquid through these grooves directly toward the corners of its mouth, where the lizard then swallows it. This unique physical adaptation allows the thorny devil to harvest moisture from its surroundings simply by standing in damp sand or encountering light precipitation.

Based on the text, what is true of the thorny devil's water-gathering process?

In architectural conservation, researchers study the degradation of limestone monuments exposed to acid rain. Limestone consists primarily of calcium carbonate ($CaCO_3$), which reacts with acid rain to form soluble compounds, causing the stone to dissolve over time. However, when monuments are treated with a protective coating of ammonium oxalate, the compound reacts with calcium carbonate to form calcium oxalate. Because calcium oxalate is highly insoluble in acidic solutions, researchers hypothesize that applying this treatment to limestone monuments will shield the stone from dissolution because ______

Which choice most logically completes the text?

Astrophysicist Dr. Niloufar Esfandiari and colleagues investigated the rotational dynamics of middle-aged main-sequence stars (stars of similar mass and evolutionary stage to the Sun). According to standard models of stellar evolution, magnetic braking—the process by which a star's magnetic field interacts with its stellar wind to shed angular momentum—continues steadily throughout a star's main-sequence lifetime, causing a continuous decline in rotation speed and magnetic activity as the star ages. However, Esfandiari and her team hypothesized that once stars reach middle age, their magnetic braking efficiency drops sharply, resulting in a state where rotation rates and magnetic activity levels remain relatively stable thereafter.

Which finding from the team's observations, if true, would most directly support the team's hypothesis?

Anthropologist Dr. Clara Zhang investigated the social functions of pottery decorative patterns among the ancient Puebloans in the American Southwest during the Pueblo III period (c. 1150–1300 CE). Some scholars argue that these complex geometric designs served primarily to identify individual household lineage. However, Zhang hypothesizes that the designs functioned as shared regional symbols to facilitate cooperative trade alliances between distinct communities during periods of resource scarcity.

Which finding, if true, would most directly support Zhang's hypothesis?

Botanist Dr. Lisa Patel studied the defense mechanisms of the wild cabbage plant (*Brassica oleracea*). Patel claimed that wild cabbage plants increase their production of mustard oils—chemical compounds that deter pests—specifically in response to insect feeding, rather than maintaining high levels of these oils constantly.

Which choice, if true, would most directly support Patel's claim?

Prior to the development of radar in the late 1930s, Great Britain relied on a network of concrete acoustic mirrors built along its southern and eastern coasts to detect incoming enemy aircraft. Designed by acoustic pioneer William Sansome Tucker, these curved structures functioned by reflecting and focusing sound waves onto a central point, where a listener equipped with stethoscopes could hear the engine noise of distant planes. While the mirrors could detect aircraft up to twenty-five miles away, their efficacy was highly contingent on ambient meteorological conditions; high winds or coastal surf could easily drown out the focused sound waves. Furthermore, the rapid increase in aircraft speeds during the 1930s rendered the detection window provided by the mirrors too narrow for effective defense mobilization, leading to the system's retirement in favor of radio-based detection.

Based on the text, which statement is true about the acoustic mirrors?

The Fleischmann’s glass frog (*Hyalinobatrachium fleischmanni*) exhibits a unique adaptation to evade predators during sleep. Researchers have found that while sleeping, the frog sequesters approximately 89 percent of its red blood cells within its liver. Because the frog's skin and muscles are translucent, hiding these pigment-rich red blood cells makes the frog's body nearly transparent, allowing it to blend seamlessly into surrounding leaves. Once the frog wakes up and becomes active, the red blood cells exit the liver and resume circulation throughout the body, restoring its typical color and activity levels.

Based on the text, what is true of a Fleischmann's glass frog when it is awake and active?

Boron isotope ratios ($\delta^{11}\text{B}$) in fossilized planktonic foraminifera shells serve as a proxy for ancient ocean pH, with lower values indicating more acidic waters. The species *Neogloboquadrina pachyderma* forms its inner chambers in shallow surface waters and its outer chambers in deeper, naturally more acidic waters. During a prehistoric warming event, rapid carbon emissions severely acidified surface waters, whereas deep-ocean pH remained temporarily stable. Researchers analyzed fossilized *N. pachyderma* shells from the onset of this event. Assuming the species maintained its vertical migration behavior, the analysis of these shells would most likely reveal that