Knowledge of Language

In the early twentieth century, astronomer Henrietta Swan Leavitt analyzed photographic plates of variable stars in the Magellanic Clouds, calculating and computing the changing brightness of these stars, which varied in luminosity over time, she discovered the period-luminosity relation.

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Before the invention of modern refrigeration, food preservation relied heavily on salting and curing techniques. Each year, people repeated these practices annually during the autumn months to prepare for winter.

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Aerogel, a synthetic ultralight material derived from a gel, consists of more than 99 percent air. Despite its light weight, it is remarkably strong and can support thousands of times its own mass. Because of its properties as an insulator, which insulate against heat, it is used by aerospace engineers for insulation in spacecraft.

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In the mid-twentieth century, geologist Marie Tharp painstakingly plotted sonar data to map the ocean floor, revealing a massive rift valley running down the center of the Atlantic. This discovery supported the theory of continental drift, which had previously been dismissed by many scientists. Through her careful charting of the ocean floor, Tharp was able to create the first comprehensive map of the ocean bottom, which was a major breakthrough that transformed the field of oceanography.

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Biologists studying deep-sea hydrothermal vents discovered a species of extremophile shrimp that thrives in superheated water. Although these organisms are currently existing today in environments that would kill most marine species, they have developed unique proteins to stabilize their cellular structure.

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Although the summit of Mount Everest is the highest point on Earth, the climb is incredibly perilous. Due to the fact that the weather is extremely cold, climbers must wear specialized gear to prevent frostbite.

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At Chichén Itzá, the Mayan pyramid known as El Castillo produces a striking acoustic effect: a handclap at the base of the stairs triggers a chirping echo that mimics the sacred quetzal bird. This unique chirping sound is believed by researchers to have been an intentional creation that the ancient architects planned on purpose by designing steps of varying depths.

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Because the team was short on time, they decided to collaborate together in cooperation to finish the project.

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Climatologists extract ice cores from deep within glaciers; these cylindrical samples of ice, which are shaped like cylinders, preserve tiny bubbles of ancient air, allowing researchers to measure greenhouse gas levels from hundreds of thousands of years ago.

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The restoration of the historic theater was delayed by several weeks because the plaster conservator had to meticulously repair the ornate ceiling, which was a time-consuming process that took a long time to complete.

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In 1856, eighteen-year-old chemist William Henry Perkin was attempting to synthesize quinine, a treatment for malaria, in his home laboratory. Instead of quinine, he produced a dark, sticky sludge that turned out to be the first synthetic aniline dye. He noticed that the sludge had a rich purple color when it was dissolved in alcohol, which was a purple color that had never been produced artificially before. Perkin quickly patented the process, launching the modern synthetic dye industry.

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Each autumn, millions of monarch butterflies undertake a massive journey from North America to the forests of central Mexico. Due to the fact that they are possessed of a need to escape the cold winter temperatures, they travel up to three thousand miles to reach their nesting sites.

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In 1964, physicists Arno Penzias and Robert Wilson were troubled by a persistent, low-frequency hum picked up by their Holmdel horn antenna. After ruling out interference from urban area signals, they meticulously cleaned the giant instrument, scrubbing away nests left by roosting pigeons. However, their efforts to eliminate the noise were unsuccessful, because the static was still heard by them, persistently continuing. Eventually, they realized they had stumbled upon the cosmic microwave background radiation, the remnant glow of the Big Bang.

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Although fireflies are best known for their glowing lanterns, not all species of these insects can actually produce light. Because of the reason that some species lack the chemical organs that are needed to glow, they rely on chemical scents called pheromones to find mates.

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To prepare for the concert, the pianist rehearsed the difficult concerto for hours. She focused on the final movement, which she practiced repeatedly over and over again to perfect her technique.

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Many modern structures rely heavily on solar energy. The efficiency of these solar panels depends in the amount of sunlight they receive daily.

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Linguists tracking the evolution of Indo-European languages have noted that sound shifts occur in highly predictable patterns; by studying these systematic changes, which proceed in an orderly fashion, researchers can reconstruct Proto-Indo-European, the ancestral tongue from which modern languages descended.

Which choice is the most effective and concise way to write the underlined portion of the sentence?

Although the young gymnast had trained for only a year, she proved she was capable to execute the difficult routine with ease. Her performance earned her a gold medal.

Which choice represents the most idiomatic phrasing for the underlined portion?

Discovered in 1901 off the Greek island of Antikythera, the ancient bronze device known as the Antikythera mechanism has long puzzled historians. Scholars, who study historical artifacts, have conducted investigations into the device's intricate system of gears, and their research has ultimately revealed that it functioned as a sophisticated astronomical calendar.

Which of the following versions of the underlined portion best produces a clear, concise, and grammatically correct sentence?

In the damp, shaded understory of temperate rainforests, certain species of fungi emit a soft, greenish glow, this glowing illumination, which shines with light, serves to attract nocturnal insects that distribute the fungi's spores.

Which choice is the most concise and grammatically correct replacement for the underlined portion of the sentence?