Topic Development

Sea otters are among the few marine mammals known to use tools. To crack open the hard shells of prey like clams and mussels, an otter will float on its back, place a flat rock on its chest, and hammer the shellfish against the rock. _Many people enjoy visiting aquariums to watch sea otters swim and play._ This tool-use behavior is not just a clever trick; it is a vital survival skill passed down from mothers to their pups.

The writer is considering deleting the underlined sentence. Should the writer make this deletion?

In the mid-twentieth century, scholars of Maya hieroglyphic writing widely believed that the inscriptions on stone monuments, or stelae, were purely astronomical calendars and mystical calculations. The prevailing view, championed by leading Mayanist J. Eric S. Thompson, held that the Maya were a peaceful, time-obsessed people whose writing did not record historical events or individuals. However, Tatiana Proskouriakoff, an architect and archaeologist, challenged this consensus through meticulous spatial and temporal analysis of the stelae at Piedras Negras. By plotting the dates inscribed on consecutive monuments, she discovered that the timespans between key dates corresponded perfectly to the natural length of a human life. Proskouriakoff proposed that these monuments actually commemorated the lifespans, accessions, and military victories of historical rulers.

The writer wants to conclude the passage with a sentence that reinforces the significance of Proskouriakoff's discovery and ties back to the paragraph's discussion of Maya writing. Which of the following sentences best accomplishes this goal?

[1] __________________________________________________ Today, visitors can check out digital tablets, attend coding workshops, and use 3D printers in maker spaces. These services demonstrate that the library is no longer just a warehouse for printed texts, but a dynamic center for modern learning and collaboration.

Which choice most effectively introduces the paragraph by establishing its main focus?

Passage Excerpt:
In the early nineteenth century, Mary Anning searched the coastline of Lyme Regis, uncovering remarkable fossils that would challenge established scientific beliefs. Hoping to make a historic discovery, she meticulously documented her finds, contributing significantly to the emerging field of paleontology.

The writer wants to replace the underlined portion to emphasize the physical challenges Anning faced while searching for fossils. Which choice best accomplishes this goal?

Sound Mirrors of Denge

Before the invention of radar, the military relied on concrete acoustic mirrors, affectionately known as "listening ears," to detect incoming enemy aircraft. Erected along the southern and eastern coasts of Great Britain during the 1920s and 1930s, these massive curved concrete structures were designed to reflect and concentrate sound waves. By focusing sound onto a microphone positioned at the focal point, listeners could detect the distant drone of airplane engines miles before they were visible to the naked eye.

The science behind the mirrors was simple yet elegant. Sound waves travel through the air and strike the curved face of the concrete bowl. Just as a curved mirror reflects light to a single point, the acoustic mirror reflected sound waves to a central collector. Operators wearing headphones would sit in nearby cabins, listening intently to the amplified static of the English Channel. If they heard a hum, they could calculate the direction of the aircraft based on which mirror received the strongest signal.

However, the rapid advancement of aviation technology quickly outpaced the capabilities of these concrete behemoths. By the mid-1930s, military aircraft were traveling at speeds that rendered the acoustic mirrors virtually useless. A plane would be detected only minutes before it arrived, leaving insufficient time to scramble defense fighter planes. The development of radar in 1935 ultimately sealed the fate of the sound mirrors, rendering them obsolete relics of a bygone era. Today, the mirrors at Denge stand as haunting monuments to a brief moment in military history.

Suppose the writer's goal had been to write an essay that traces the transition from acoustic detection technology to electromagnetic detection systems in early twentieth-century military defense. Would this essay accomplish that goal?

A researcher is writing a short article about the history of medicine:

When Alexander Fleming returned to his laboratory after a vacation in 1928, he noticed something unusual in one of his petri dishes. A patch of mold had grown, and the bacteria immediately surrounding it had been destroyed. This accidental observation led to the discovery of penicillin, the world's first antibiotic.

Which choice best concludes the paragraph by emphasizing the historical significance of Fleming's discovery?

Emily Warren Roebling's Bridge

[1]
In $1872$, when chief engineer Washington Roebling became bedridden with caisson disease (commonly known as "the bends") while supervising construction of the Brooklyn Bridge, the monumental project faced an immediate crisis. His wife, Emily Warren Roebling, stepped into the breach. Although she did not possess a formal degree in engineering, she possessed a keen intellect and a determined spirit. She began by taking detailed notes, carrying messages between her husband and the construction site, and translating complex mathematical calculations.

[2]
As the years progressed, Emily's duties expanded far beyond those of a mere messenger. She undertook a rigorous self-study of civil engineering, materials science, cable construction, and stress analysis. Soon, she was representing her husband at meetings with trustees, inspectors, and contractors, ensuring that the daily operations of the massive public works project proceeded without interruption. Her deep understanding of the project's technical demands earned her the respect of both the bridge's builders and its stakeholders.

[3]
When the Brooklyn Bridge officially opened in $1883$, Emily Warren Roebling was the first person to cross it in a carriage, carrying a rooster as a symbol of victory. Her contribution, though largely uncredited in official annals for decades, was essential to the completion of the bridge. The structure stands today not only as a feat of nineteenth-century engineering but also as a testament to her perseverance and intellectual adaptability.

Suppose the writer's goal had been to write an essay that profiles the specific technical engineering innovations developed to construct the Brooklyn Bridge. Would this essay fulfill that goal?

In 1840, Great Britain introduced the Penny Black, the world's first adhesive postage stamp. Prior to its release, postage was paid by the recipient rather than the sender, and the rate was calculated based on the distance the letter traveled. The Penny Black simplified this system by establishing a flat rate of one penny, regardless of distance, as long as the letter weighed under half an ounce.

The writer is considering adding the following sentence to the end of the passage:

"Stamps are now collected by millions of people worldwide as a popular hobby called philately."

Should the writer make this addition?

Cooling with the Cosmos

[1]
In an era dominated by mechanical air conditioning, which consumes vast amounts of electricity and relies on potent greenhouse gases, engineers are turning to an ancient thermodynamic principle: radiative cooling. All objects emit thermal radiation in the form of electromagnetic waves, primarily infrared light. Normally, Earth's atmosphere acts as a thermal blanket, absorbing and re-emitting this heat back to the surface. However, there exists a narrow spectral window—between wavelengths of 8 and 13 micrometers—where the atmosphere is highly transparent. In this "sky window," infrared radiation emitted from the Earth's surface passes directly through the atmosphere and escapes into the freezing void of outer space.

[2]
Historically, passive radiative cooling was only effective at night, as daytime solar radiation easily overwhelms the cooling effect. To achieve daytime radiative cooling, researchers in the 2010s developed specialized metamaterials. These materials are engineered to reflect over 95 percent of incoming solar radiation while simultaneously emitting thermal energy in the 8-to-13 micrometer infrared range. By applying these ultra-reflective, selectively emissive films to roofs, buildings can cool themselves below the ambient air temperature without consuming any electricity, even under direct sunlight.

[3]
While the potential energy savings of this technology are immense, widespread adoption faces significant hurdles. Current metamaterials are expensive to produce at scale and tend to degrade when exposed to harsh outdoor weathering. Furthermore, radiative cooling is least effective in humid regions, where atmospheric water vapor absorbs the outgoing infrared radiation, effectively closing the sky window. Nevertheless, as researchers refine these materials, passive cooling could become a cornerstone of sustainable urban design, utilizing the cold expanse of the universe as a natural heat sink.

Suppose the writer's goal had been to write an essay explaining the physical principles behind passive radiative cooling and the constraints currently preventing its commercial viability. Is the statement that this essay successfully fulfills that goal true or false?

[1]
In 1964, radio astronomers Arno Penzias and Robert Wilson were using a large horn antenna at Bell Telephone Laboratories in Holmdel, New Jersey, to detect weak radio signals from the spaces between galaxies. However, their efforts were frustrated by a persistent background hiss that was louder than expected. The noise did not vary by day, night, or season, suggesting it did not originate from the sun or a localized celestial source.

[2]
Determined to isolate the source of the interference, the pair systematically checked their equipment. They pointed the antenna toward New York City to see if urban radio broadcasts were responsible, but the hiss remained constant. They even cleaned the antenna of pigeon droppings that had accumulated inside the horn, yet the mysterious static persisted. Penzias and Wilson were out of conventional explanations.

[3]
Meanwhile, physicists at nearby Princeton University led by Robert Dicke were theorizing that if the Big Bang had occurred, it would have left behind a faint, uniform remnant radiation throughout the universe. When Dicke heard of the Bell Labs scientists' unexplained static, he realized they had found exactly what his team was searching for. Penzias and Wilson had accidentally detected the cosmic microwave background radiation, a discovery that earned them the 1978 Nobel Prize in Physics and provided crucial evidence for the Big Bang theory.

Suppose the writer's goal had been to write an essay that describes how a major scientific discovery was made through accidental observations rather than planned experimentation. Would this essay fulfill that goal?

The following sentences are taken from a draft of an essay about animal navigation. To ensure that the paragraph logically develops its claim about how desert ants find their way and supports it with necessary details, what is the most logical order for these sentences?

Consider the following paragraph:

[1] __________________________________________________ Before its development, early bicycles like the 'penny-farthing' featured a massive front wheel and a tiny rear wheel, making them extremely difficult to mount and prone to dangerous forward crashes. In 1885, John Kemp Starley introduced the safety bicycle, which featured two wheels of equal size, a chain drive, and a steerable front wheel. This new design made bicycling accessible and safe for the general public, triggering a cycling craze in the late nineteenth century.

The writer wants to begin the paragraph with a sentence that establishes the main topic. Which of the following choices best accomplishes this goal?

In 1970, when graphic designer Hiroshi Ohchi founded the design journal *Idea*, he sought to bridge the aesthetic gap between Japanese traditional art and Western modernism. Ohchi believed that the clean lines of Bauhaus could find common ground with the minimalist principles of Zen. Ohchi wanted the journal to serve as an international forum for graphic design trends. Consequently, the journal became a global platform, introducing avant-garde Japanese typography to international audiences.

The writer wants to replace the bolded text with a statement that provides a specific, concrete example of how Ohchi blended Japanese traditional art and Western modernism in the journal's early layouts. Which choice best fulfills this goal?

In 1977, oceanographers exploring the Galapagos Rift made a startling discovery. Deep on the ocean floor, where no sunlight could penetrate, they found hydrothermal vents spewing superheated, mineral-rich water. Instead of finding a barren wasteland, they observed thriving ecosystems teeming with giant tube worms, blind crabs, and vast colonies of bacteria. These organisms did not rely on photosynthesis; instead, they survived on chemical energy through a process called chemosynthesis.

The writer wants to add a concluding sentence to the paragraph that wraps up the discussion of chemosynthesis and reinforces the main idea of the passage (that this discovery revealed a new way life can thrive without sunlight). Which of the following sentences best accomplishes this goal?

Passage Excerpt:

In 1957, inventors Alfred Fielding and Marc Chavannes sealed two plastic shower curtains together, creating a sheet of trapped air bubbles. They originally hoped to market this textured material as a trendy three-dimensional wallpaper. ________ Finally, in 1960, IBM began using the material to protect its fragile computers during shipping, launching the product's global success as Bubble Wrap.

Given that all the choices are true, which choice most effectively emphasizes the contrast between the inventors' high expectations for their wallpaper and the actual market response?

The following passage is from an essay about maritime archaeology.

**The Preservation of the *Mary Rose***

[1] In 1982, the Tudor warship *Mary Rose* was raised from the Solent seabed after four centuries underwater. [2] The ship’s wooden hull, though remarkably intact, was highly vulnerable to rapid decay once exposed to the air. [3] To prevent the waterlogged oak from shrinking and warping as it dried, conservationists sprayed the hull with polyethylene glycol (PEG), a water-soluble polymer. [4] Over several decades, PEG slowly penetrated the wood cells, replacing the water and supporting the cell walls. [5] Archeologists also recovered thousands of artifacts from the site, including longbows, leather shoes, and pewter plates. [6] Once the wood was fully stabilized, the spraying was stopped, allowing the hull to be slowly air-dried for public display.

The writer is considering deleting Sentence 5 from the passage. Should the writer make this deletion?

In 1756, British civil engineer John Smeaton was commissioned to rebuild the Eddystone Lighthouse, a structure off the coast of Devon that had repeatedly succumbed to the brutal storms of the English Channel. Smeaton recognized that standard mortar, which required exposure to air to set, would dissolve long before it could cure in the spray of the sea. To address this challenge, he conducted a series of rigorous experiments testing various lime mixtures. He discovered that limestone containing a high proportion of clay, when mixed with volcanic ash, created a hydraulic mortar that actually hardened underwater. This breakthrough allowed Smeaton to successfully complete the lighthouse and laid the foundation for modern cement. Roman builders had previously used a similar mix of volcanic ash and lime to build the Pantheon, which still stands today.

Given the context of the paragraph, should the writer make this deletion?

Deep-Sea Oasis

[1]
For generations, oceanographers operated under a fundamental assumption: all marine life ultimately depended on sunlight. Photosynthetic phytoplankton at the ocean's surface formed the base of the marine food web. It was believed that the abyssal plains, shrouded in perpetual darkness, could support only a sparse population of scavengers relying on "marine snow"—organic debris drifting down from above.

[2]
This view was shattered in 1977 during an expedition in the Pacific Ocean near the Galápagos Islands. Researchers aboard the submersible Alvin descended more than 2,500 meters to the ocean floor. Instead of a barren desert, they discovered hydrothermal vents spewing superheated, mineral-rich water. Surrounding these vents were dense, thriving ecosystems teeming with giant tube worms, blind crabs, and massive clams, all thriving in conditions previously thought to be completely uninhabitable.

[3]
The key to this thriving community was chemosynthesis, a process completely independent of sunlight. Specialized bacteria utilized the toxic hydrogen sulfide dissolved in the vent fluids to produce organic molecules, serving as the primary producers for this alien ecosystem. This discovery revolutionized our understanding of life's adaptability and opened new possibilities for where life might exist elsewhere in the universe.

Suppose the writer's goal had been to write an essay that describes how a major scientific discovery challenged a long-held biological assumption. Would this essay successfully fulfill that goal?

[1] In the early nineteenth century, Mary Anning patrolled the crumbling cliffs of Lyme Regis, England, uncovering fossils that would challenge established scientific doctrines about the history of the Earth. Despite her lack of formal education, Anning possessed an extraordinary talent for locating and excavating specimens. Her discoveries, which included the first correctly identified ichthyosaur skeleton and a nearly complete plesiosaur, provided crucial evidence for the emerging theory of extinction.

[2] At the time, many scientists believed that species did not go extinct, arguing that all creatures created by God must still exist somewhere on the globe. Anning's fossils, however, depicted bizarre, ancient marine reptiles that resembled no living animals. Her work forced the scientific community to acknowledge that the prehistoric world was vastly different from the modern one. _________

The writer wants to conclude the passage with a sentence that emphasizes the historical significance of Anning’s discoveries and ties back to the main idea of the passage. Which of the following choices best accomplishes this goal?

Before the advent of modern bioinformatics, Margaret Dayhoff revolutionized biochemistry by organizing vast amounts of biological data. In 1965, she published the first volume of the *Atlas of Protein Sequence and Structure*, a compendium that compiled all known protein sequences. [1] Dayhoff was determined to make this information accessible to researchers worldwide, envisioning a future where computational tools would decode the molecular blueprints of life. To achieve this, she developed a one-letter code for amino acids, which significantly reduced the data storage requirements for early computers.

The writer wants to add a sentence at Point [1] that highlights the challenges Dayhoff faced in obtaining protein sequences from global researchers during a period of limited communication technology. Which choice most effectively accomplishes this goal?