Establishing Introductions and Thesis Statements

Chladni Patterns

In 1787, German physicist and musician Ernst Chladni published *Discoveries in the Theory of Sound*, a seminal work that laid the foundation for modern acoustics. [1] __________________________________________________ Chladni’s technique was elegant in its simplicity: he drew a violin bow along the edge of a metal plate covered with a thin layer of sand. As the plate vibrated at specific frequencies, the sand drifted away from the moving parts (nodes) and settled along the stationary lines (nodal lines), forming intricate geometric patterns. These visual representations of sound waves, now known as 'Chladni patterns,' provided the first systematic method for analyzing how physical materials vibrate.

Which of the following choices, if inserted at [1], would provide the most effective introduction to the passage by establishing its central focus?

The writer is considering adding a sentence at the beginning of the passage (before sentence 1):

[1] For centuries, the Julian calendar, introduced by Julius Caesar in $46$ BCE, served as the primary method of tracking time in the Western world. However, the Julian system calculated the solar year as exactly $365.25$ days, which was approximately $11$ minutes and $14$ seconds longer than the actual astronomical year. While this discrepancy seemed negligible in the short term, it accumulated over centuries, drifting by one full day every $128$ years. By the sixteenth century, this error had shifted the calendar by ten days, disrupting the scheduling of Easter and other seasonal festivals.

[2] To address this compounding error, Pope Gregory XIII assembled a team of astronomers and mathematicians led by Aloysius Lilius. In $1582$, the Gregorian calendar was introduced, implementing a refined system for leap years: centurial years would only be leap years if they were divisible by $400$. To correct the accumulated drift, ten days were eliminated from October $1582$, meaning that the day following October $4$ was designated as October $15$. Although met with initial resistance, this system gradually achieved global adoption, aligning human timekeepers with the rhythm of the stars.

Which of the following choices for the proposed sentence most effectively introduces the main topic of the passage?

Cellulose nitrate served as the primary base for motion picture film from the inception of cinema until the early 1950s, lauded for its luminous quality and high tensile strength. However, this compound is notoriously unstable: it is highly flammable, prone to spontaneous combustion under ambient conditions, and susceptible to auto-catalytic decay that reduces the film to an acidic, highly combustible powder. [1] __________________________________________________ Consequently, archives worldwide must house these fragile historical documents in specialized, sub-freezing vaults designed to suppress chemical degradation and mitigate fire hazards.

Which choice most effectively introduces the paragraph's discussion of the specialized storage and safety measures required to preserve cellulose nitrate film?

Hilma af Klint

[1] __________________________________________________ Long before Vasily Kandinsky, Piet Mondrian, and Kazimir Malevich were credited with pioneering abstract art, the Swedish artist had quietly created a massive body of non-representational paintings. Influenced by spiritualism and the natural world, af Klint believed the world was not ready for her visionary art, which featured vibrant geometric shapes and biomorphic forms. Consequently, she stipulated in her will that her paintings must not be displayed to the public until twenty years after her death.

Which choice most effectively introduces the paragraph and establishes the central subject of the passage?

______ In 1943, marine engineer Richard James was working in a shipyard, trying to develop springs that could support and stabilize sensitive marine instruments. After accidentally knocking one of the steel springs from a shelf, he watched in amazement as it did not merely fall, but rather "stepped" down from a stack of books, to a tabletop, and then to the floor, where it coiled itself back up. James immediately saw the toy's potential, and his wife, Elizabeth, named it the "Slinky" after searching the dictionary for a word that described the spring's sleek, fluid movement.

Which choice most effectively introduces the paragraph?

Brunelleschi’s Dome

[1] __________________________________________________ In the early fifteenth century, the city of Florence faced a seemingly intractable architectural dilemma: the great cathedral of Santa Maria del Fiore had been built with a massive octagonal opening for a dome, but no one knew how to construct a vault of such immense proportions without it collapsing under its own weight. The traditional method of using temporary wooden scaffolding, or centering, was impossible because the Tuscan forests could not provide timbers long or strong enough to span the 143-foot gap at a height of 180 feet.

Filippo Brunelleschi, a goldsmith and clockmaker by training rather than a traditional mason, proposed a radical solution: a double-walled dome built without scaffolding. By arranging the bricks in a herringbone pattern and incorporating a series of interlocking stone and iron chains to counteract the outward tension, he successfully completed the dome in 1436. His triumph not only redefined the Florentine skyline but also marked the transition from medieval craftsmanship to modern engineering, demonstrating that mathematical precision and innovative design could overcome physical limitations previously deemed absolute.

Given that all the choices are true, which choice most effectively introduces the passage by establishing its central thesis?

[1]
For decades, marine biologists assumed that the coelacanth, a prehistoric fish with limb-like lobed fins, had gone extinct approximately 66 million years ago. However, in 1938, a museum curator named Marjorie Courtenay-Latimer discovered one among a local fisherman's catch in South Africa. This astonishing find shocked the scientific community, proving that these ancient creatures were still swimming in the deep ocean.

[2]
__________________________________________________ Before this discovery, scientists could only study the coelacanth through fossilized remains. Courtenay-Latimer's finding allowed researchers to examine a living specimen, leading to groundbreaking insights into the evolutionary transition from fish to tetrapods. Today, the coelacanth remains a living testament to the mysteries that still lie hidden in the ocean depths.

Which of the following sentences, if added at the beginning of Paragraph 2, would provide the most effective introduction and transition to the paragraph's discussion of the discovery's scientific impact?

The following is an excerpt from an essay about an ancient artifact.

In 1900, sponge divers seeking shelter from a storm off the Greek island of Antikythera stumbled upon a Roman-era shipwreck. Among the statues and coins recovered was a corroded, lumpish fragment of bronze. For decades, it sat largely ignored in a museum. However, subsequent X-ray imaging in the late twentieth century revealed a complex system of interlocking gears. This device, dating back to the second century BCE, is now recognized as the world's oldest known analog computer, capable of predicting astronomical positions and eclipses with baffling accuracy.

[1] __________________________________________________ The device's sophisticated design, which predates similar European mechanical clocks by over a millennium, suggests that ancient Greek technology was far more advanced than historians had previously assumed. By tracking the cycles of the Sun and Moon, the mechanism not only served practical calendrical purposes but also reflected a deep philosophical commitment to mapping the cosmos.

Which choice, if added at placeholder [1], most effectively introduces the second paragraph while aligning with the passage's focus on the device's historical and technological significance?

[1]
__________________________________________________ Before 1977, scientists believed that all marine life ultimately depended on sunlight, which powers photosynthesis in surface waters. However, when the research submersible Alvin descended to the ocean floor near the Galápagos Rift, researchers discovered thriving ecosystems clustered around vents spewing mineral-rich water at temperatures up to 750°F. Rather than depending on solar energy, these communities relied on chemosynthetic bacteria, which convert toxic hydrogen sulfide into organic matter.

Which of the following choices best introduces the paragraph by establishing its main focus?

Yellowstone National Park is famous for its geothermal features, such as geysers and hot springs. Among these, Old Faithful is the most renowned, drawing millions of visitors each year who wait to watch its predictable eruptions.

[1] ____________________. Due to the high concentration of silica in the hot water, a unique glass-like rock forms around the geysers. This mineral crust, known as siliceous sinter, creates the distinct mounds and terraced structures that characterize Yellowstone’s volcanic landscape.

Which choice, if inserted at the blank in Paragraph [1], would most effectively introduce the main topic of the paragraph?

The following is an excerpt from an essay about early Earth's climate.

[1]
In $1972$, astronomers Carl Sagan and George Mullen pointed out a puzzling contradiction that threatened our understanding of Earth's early history. According to standard astrophysical models, our sun was about $30$ percent dimmer during the Archean Eon, four billion years ago, than it is today. With so little solar energy reaching the planet, Earth should have been a frozen wasteland, completely locked in ice. Yet, geological evidence from that same period—such as water-worn pebbles and ancient sedimentary rocks—reveals that liquid water flowed abundantly across the surface, and primitive life was already thriving.

[2]
To resolve this paradox, researchers have proposed various atmospheric models. One prominent theory suggests that a dense greenhouse gas envelope, consisting of carbon dioxide and perhaps ammonia or methane, acted as a heavy blanket to trap what little heat the faint sun provided. Others argue that Earth's lower albedo, or reflectivity, allowed the surface to absorb more solar radiation than it does today. Understanding how Earth maintained its liquid oceans during this period is not just a historical curiosity; it also helps astronomers define the boundaries of habitable zones around distant stars.

Which choice provides the most effective transition from the first paragraph to the second paragraph and introduces the main topic of the second paragraph?

[1] Fleming returned to his laboratory after a vacation to find that a mold called *Penicillium notatum* had contaminated one of his petri dishes. To his surprise, the bacteria immediately surrounding the mold had been destroyed. This chance discovery revolutionized modern medicine, leading to the development of antibiotics that have since saved millions of lives.

Which choice most effectively introduces the paragraph?

Consider the following passage:

Umbrellas have a long history, dating back to ancient Egypt and Mesopotamia, where they were used primarily to shade royalty from the sun. In these early societies, umbrellas were symbols of power and status, made from palm leaves, feathers, or stretched papyrus. However, it was not until much later in ancient China that umbrellas were first waterproofed with wax and lacquer to provide protection against the rain.

[1] _________________________________________. For centuries, European men viewed them as a feminine accessory, associated almost exclusively with women of high social standing. It was not until the mid-eighteenth century, when an English traveler named Jonas Hanway began carrying an umbrella in public, that the device gained acceptance among men. Despite initial ridicule from carriage drivers who feared losing business, Hanway’s persistence eventually paid off, transforming the umbrella into a common and practical accessory for everyone.

Which of the following choices best introduces the main topic of the second paragraph?

Mary Anning was a pioneering English paleontologist who made several groundbreaking fossil discoveries in the cliffs of Lyme Regis. However, her path to success was not easy.

[1] She had many hobbies that kept her busy throughout her adult years. As a woman in nineteenth-century Britain, she was not allowed to join the Geological Society of London, and she was often excluded from the scientific community. Furthermore, male scientists frequently published academic papers about the fossils she found without giving her any credit.

Which choice most effectively replaces the underlined portion to introduce the paragraph by establishing its main focus?

Given the following paragraph:

[1] __________________. In 1943, Cousteau and engineer Émile Gagnan co-invented the Aqua-Lung, an open-circuit scuba technology. This revolutionary device allowed divers to breathe underwater without being tethered to a surface air supply. Armed with this new freedom, Cousteau spent decades filming underwater documentaries, bringing the mysteries of the deep ocean into the living rooms of millions of viewers worldwide.

Which choice provides the most effective introduction to the paragraph?

[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?

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?

Honeybee colonies rely on a complex system of communication to thrive. [1] __________________________________________________ By performing this figure-eight movement, a successful foraging bee can communicate the direction and distance to a rich source of nectar or pollen to other members of the hive. This dance is so precise that it accounts for the angle of the sun and the distance from the hive, allowing other bees to locate food sources miles away with incredible accuracy.

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

Ada Lovelace was a visionary mathematician who is widely celebrated today for her work on Charles Babbage’s mechanical computer.

[1] __________________________________________________ She appended a set of notes that was longer than the article itself. These notes included what is now recognized as the first computer program: an algorithm designed to calculate Bernoulli numbers. Lovelace saw that Babbage’s machine could do more than just compute numbers; she envisioned it processing symbols, music, and art, laying the conceptual groundwork for modern computing.

Which choice most effectively introduces the paragraph?

Maya Hieroglyphs

[1] __________________________________________________ Historically, scholars like Eric Thompson argued that the glyphs were merely logographic symbols representing dates and astronomical concepts, with no phonetic elements. This view dominated Mayanist studies for decades, creating a consensus that Mayan writing could never be read phonetically. However, in the mid-twentieth century, Yuri Knorozov, a Soviet linguist, proposed that the glyphs represented syllables in addition to logograms. By comparing the signs in the surviving codices with spoken Mayan languages, Knorozov demonstrated that the script could indeed transcribe the sounds of spoken language, a breakthrough that revolutionized the field of Mesoamerican archaeology.

Knorozov's phonetic approach met with fierce resistance from the established academic community, but it eventually gained traction as other researchers successfully deciphered names, dynasties, and historical events recorded on monuments. The resulting translations transformed our understanding of Classic Maya society from a peaceful, stargazing civilization into one of complex political alliances, warfare, and rich literature.

The writer wants to begin the passage with a sentence that establishes its main focus: the shift in how scholars understood Mayan hieroglyphs. Which of the following sentences, if added at [1], would best accomplish this goal?