영어 모의고사 (자동 편성)

Long before humans learned to drill for oil, microorganisms had already mastered the art of ①converting sunlight and carbon dioxide into stored chemical energy. Modern biofuel research borrows this ability, cultivating algae or engineered bacteria in large tanks where they can be ②coaxed into producing oils and sugars that can be refined into fuel usable in existing engines. Unlike crops grown for corn-based ethanol, which compete directly with food production for arable land, many algae strains can ③thrive in shallow ponds, wastewater, or even coastal seawater unsuitable for conventional agriculture. Engineers have also learned to tinker with the metabolic pathways of these organisms, ④boosted oil yield far beyond what any wild strain would naturally produce on its own. Despite this progress, producing biofuel at a cost competitive with fossil fuel remains difficult, since harvesting and processing the organisms consumes a substantial share of the energy the fuel itself will eventually ⑤provide.

Desalination, the process of removing dissolved salts from seawater to produce fresh water, has increasingly been adopted by coastal regions facing chronic water ①scarcity. Most modern facilities rely on reverse osmosis, a technique in which seawater is forced through membranes whose microscopic pores block salt while letting water molecules pass. Because this method ②consumes far less energy than the thermal distillation once dominant in the industry, it has become the preferred choice for large-scale plants. Nevertheless, desalination remains an inherently costly and environmentally burdensome solution, a fact often overlooked amid enthusiasm for ending water shortages. For instance, the process generates a ③concentrated byproduct called brine, which, when discharged without adequate dilution, can raise local salinity to levels that harm marine life. Pumping seawater through membranes at high pressure also demands substantial electricity, so plants powered by fossil fuels can ④alleviate the emissions that intensify drought. Therefore, engineers increasingly argue that desalination should be treated not as a stand-alone remedy but as one component of a ⑤broader conservation strategy.

When people evaluate their personal contribution to water scarcity, they often consider only the water that flows directly from household taps, overlooking a far larger quantity consumed indirectly through the goods they purchase. The water footprint, a concept that extends this ①broad view, measures the total volume of freshwater used to produce the goods and services an individual or a nation consumes. Central to this concept is the notion of virtual water, the water embedded ②invisibly within a product, from irrigating cotton fields to livestock raised for meat. For instance, producing a kilogram of beef can require several thousand liters of water, whereas a kilogram of vegetables typically demands a fraction of that amount. Nations that import water-intensive goods rather than producing them domestically are importing virtual water from regions that may face ③severe shortages. Critics caution, however, that focusing ④exclusively on aggregate volume can mislead policymakers, since a liter of water drawn from a region suffering drought carries far greater consequences than one drawn from a water-⑤abundant area.

A cricket contains, gram for gram, roughly as much protein as beef, yet requires a small fraction of the land, water, and feed needed to raise cattle. This efficiency has drawn growing attention from researchers looking for ways to feed a global population that continues to climb while arable land remains essentially fixed. Insects also convert feed into body mass with remarkable efficiency, since they are cold-blooded and therefore spend far less energy regulating body temperature than a cow or pig must. _______________. Food companies have responded by grinding insects into a flour that disappears into protein bars, pasta, and baked goods, letting consumers benefit from the nutrition without ever having to look an insect in the eye.

Bacteria have been cutting up invading viral DNA for billions of years, long before any scientist thought to borrow the trick for use in a laboratory. The CRISPR-Cas9 system relies on a short guide RNA that matches a specific DNA sequence, _______________. Once Cas9 arrives at the target site, it slices both strands of the DNA helix, and the cell's own repair machinery rushes in to mend the cut, often introducing a small change in the process. By supplying the cell with a template during this repair step, scientists can direct that machinery to insert a specific new sequence rather than merely disabling the original gene. What once required years of painstaking work to alter a single gene can now be accomplished within days.

As buildings account for a substantial share of global energy consumption, architects have increasingly turned to a design philosophy known as the passive house standard, which minimizes energy demand through the building's own structure rather than through mechanical systems. (A) Consequently, many architects regard passive house design not as a luxury for wealthy homeowners but as a practical model capable of reshaping mainstream construction. (B) Central to this approach is airtight construction, in which continuous insulation and sealed joints prevent conditioned air from leaking outward, thereby reducing the heating and cooling loads conventional buildings require. Triple-glazed windows, oriented to capture sunlight in winter while shading interiors in summer, further stabilize indoor temperatures without relying heavily on furnaces or air conditioners. (C) Ventilation systems equipped with heat exchangers also recover warmth from outgoing air, transferring it to incoming air so that comfort is maintained without excessive energy use. For example, some passive houses built in cold climates have reduced heating costs by more than ninety percent.

When anthropologists first began systematically studying societies far removed from their own, many unconsciously judged unfamiliar customs against the standards of their home culture, a tendency now known as ethnocentrism. (A) Anthropologist Franz Boas argued that no culture possesses an inherently superior set of values, and that apparent oddities, once examined closely, typically serve coherent functions within their own social systems. (C) Cultural relativism emerged as a corrective principle, holding that a society's practices should be understood within their own cultural context rather than measured against an outside standard presumed to be universal. (B) Critics caution, however, that taken to an extreme, the principle risks excusing practices that cause genuine harm.

Social unrest does not always emerge from the poorest conditions; it frequently erupts when circumstances are improving but not quickly enough to satisfy rising expectations. (A) Political scientist Ted Gurr illustrated the pattern with what is often called the J-curve: revolutions tend to follow a period of sustained improvement that is then followed by a sudden reversal. (B) This paradox lies at the heart of relative deprivation theory, which holds that discontent arises less from objective hardship than from a perceived gap between what people expect and what they actually receive. (C) Because the theory centers on perception rather than raw statistics, it helps explain why relatively prosperous societies can experience intense protest while long-impoverished societies sometimes remain comparatively quiet.

Weak ties, precisely because they connect otherwise separate networks, transmit novel information more efficiently than the redundant, overlapping ties within a tightly bonded group. Sociologist Mark Granovetter challenged a common assumption when he found that job seekers were more likely to hear about new opportunities from casual acquaintances than from close friends and family. ( ① ) This finding, published as the strength of weak ties, rests on a structural insight. ( ② ) Close friends tend to belong to the same tight social circle and therefore already share most of the same information. ( ③ ) Casual acquaintances, by contrast, typically move in different circles and can act as bridges to information a person would otherwise never encounter. ( ④ ) Granovetter's insight has since been applied well beyond job searches, informing research on how innovations spread and how epidemics travel through a population. ( ⑤ )

Even so, the shift has proven immensely practical, sidestepping the objection that halted so much earlier research. A single fertilized egg eventually gives rise to every cell type in the human body, from neurons to bone, a feat that has fascinated biologists for more than a century. ( ① ) Embryonic stem cells retain much of that original versatility, capable in principle of developing into almost any tissue, which is why researchers have long viewed them as a promising raw material for repairing damaged organs. ( ② ) Because harvesting these cells traditionally required destroying a human embryo, the research provoked ethical objections fierce enough to slow funding and legislation in several countries for years. ( ③ ) A breakthrough arrived when scientists discovered that ordinary adult skin cells could be reprogrammed, through the introduction of a handful of specific genes, into a state resembling embryonic versatility without ever touching an embryo. ( ④ ) These induced pluripotent cells, as they are now called, have not entirely erased the ethical debate. ( ⑤ ) They have opened a path for stem cell research that far more scientists and funding agencies are willing to support.