영어 모의고사 (자동 편성)

A printer that once produced only plastic prototypes can now ①deposit living cells layer by layer to build a structure that begins to resemble actual tissue. Bioprinting adapts the logic of conventional 3D printing, ②replacing plastic filament with a specialized ink made of living cells suspended in a gel that supports their survival while the shape sets. Printing a flat patch of skin or a simple blood vessel has already moved from laboratory curiosity to early clinical testing, since these tissues ③is thin enough for nutrients to reach every cell by diffusion. Printing a solid organ such as a kidney remains a far greater challenge, because internal cells starve without their own blood supply, and no printer yet exists that can build a network of vessels fast enough ④to keep them alive. Researchers are therefore focusing on hybrid strategies, printing a rough scaffold and then ⑤allowing the tissue to mature and grow its own vasculature over time.

When a country physician named Edward Jenner noticed that milkmaids ①who had caught cowpox seemed immune to smallpox, he set in motion a medical revolution without fully understanding why it worked. For nearly two centuries afterward, vaccine development proceeded largely by trial and error, ②weakened or killing a pathogen and testing whether the resulting preparation could train the immune system without causing disease itself. This method produced genuine successes, eventually eliminating smallpox worldwide and reducing diseases such as polio and measles, but each new vaccine still ③required years of laboratory work with no guarantee of success. Advances in molecular biology eventually allowed researchers ④to isolate a single protein from a pathogen's surface rather than using the whole organism, producing vaccines with fewer side effects and a more predictable safety profile. The most recent shift, toward delivering genetic instructions rather than proteins themselves, represents the latest chapter in a story ⑤that began with an eighteenth-century doctor's curiosity about a puzzling immunity among dairy workers.

The ancient puzzle known as the ship of Theseus asks a deceptively simple question. If every plank of a wooden ship is replaced one by one over many years, is the vessel that eventually results still the same ship it once was? Most people's first instinct is to answer yes, since each individual replacement seems too small to erase the ship's identity. The puzzle grows far sharper, however, once a second twist is introduced. Suppose a careful collector gathered every discarded plank and reassembled them into a second vessel, built exactly as the original once stood. Two ships would then exist side by side, each with an equal claim to being the genuine one, and no obvious way to decide between them. Philosophers return to this old story again and again, not because they care about timber, but because it forces us to ask whether identity depends on continuous material, continuous form, or _______________.

For much of the twentieth century, memory researchers assumed that once a memory had been consolidated—transformed from a fragile, short-term trace into a stable, long-term representation—it remained essentially fixed, immune to further modification unless the underlying neural circuitry was physically damaged. This assumption, however, was overturned by a body of research demonstrating that _______________, rendering it temporarily susceptible to alteration before it is, in a sense, filed away again. During this narrow window, which typically lasts only a few hours, the memory can be strengthened, weakened, or even subtly distorted by new information encountered in the interim, after which it must undergo a second round of stabilization, a process now widely referred to as reconsolidation. Consequently, what we experience as a stable recollection may actually be a continuously revised construction, reshaped every time it is summoned into conscious awareness and returned to storage.

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.

Blockchain technology was originally promoted as a way to remove the need for trusted middlemen, allowing strangers to exchange value directly through a shared, tamper-resistant ledger. (A) In practice, however, a small number of large players have come to dominate many blockchain networks, controlling enough power to influence outcomes that were supposed to be decided collectively. (B) In theory, this design distributes power away from any single institution and toward the network as a whole. (C) Critics note a further irony: when something goes wrong, there is often no institution left to appeal to, since the system was designed to eliminate central authority.

Labeling theory approaches deviance not as a fixed property of certain acts, but as a social process created when powerful groups attach a negative label to a person's behavior. (A) Once labeled, an individual may find legitimate opportunities closing off, pushing them toward the very community of offenders that the label predicted they would join. (B) According to this view, nearly everyone breaks minor rules at some point, yet only some individuals are singled out and formally branded as delinquents or criminals. (C) This process, sometimes called secondary deviance, illustrates how social reaction can produce the outcome it claims merely to describe.

When people recall precisely where they were and what they were doing at the moment they learned of some momentous public event, the resulting memory often feels extraordinarily vivid, as though it had been etched into the mind with photographic precision; researchers have termed such recollections flashbulb memories. (A) Proponents of this concept once argued that the emotional intensity and surprise accompanying such events trigger a distinct neural mechanism that preserves details with unusual fidelity, effectively exempting them from the gradual decay that afflicts ordinary memories. (B) This persistent mismatch between subjective certainty and objective consistency implies that flashbulb memories, far from being flawless recordings, are reconstructed narratives shaped by rehearsal, media exposure, and the passage of time. (C) Subsequent longitudinal studies, however, have complicated this picture considerably: when researchers compared accounts gathered within days of an event to accounts gathered years later, they discovered that details had frequently been altered, omitted, or even fabricated, even though the individuals reporting them expressed unwavering confidence in their accuracy.

Long before humans learned to drill for oil, microorganisms had already mastered the art of converting sunlight and carbon dioxide into stored chemical energy. (A) Modern biofuel research borrows this ability, cultivating algae or engineered bacteria in large tanks where they can be coaxed into producing oils and sugars that can be refined into fuel usable in existing engines. (B) Unlike crops grown for corn-based ethanol, which compete directly with food production for arable land, many algae strains can thrive in shallow ponds, wastewater, or even coastal seawater unsuitable for conventional agriculture. (C) Engineers have also learned to boost oil yield through genetic tinkering, yet 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 provide.

Turning this tide has proven far harder than creating it, and not merely for scientific reasons. Every time an antibiotic kills off a population of bacteria, a handful of cells carrying a random mutation that resists the drug are left behind to multiply without competition. ( ① ) Repeated over decades, across hospitals, farms, and households worldwide, this simple process of natural selection has produced strains of bacteria that survive treatments once considered reliably effective. ( ② ) The pharmaceutical industry, meanwhile, has slowed the pace at which new antibiotics reach the market, since a drug meant to be taken for only a week or two rarely earns back the enormous cost of developing it. ( ③ ) Researchers are therefore searching in unconventional places, screening soil microbes and ocean sediment for molecules that kill bacteria through new mechanisms. ( ④ ) Even genetic databases are now mined for such molecules, ones resistant strains have not yet learned to evade. ( ⑤ ) Some scientists have also revived an older approach, using viruses that infect only bacteria to hunt down resistant strains with a precision no broad-spectrum drug could ever match.