Commas with Nonessential and Parenthetical Elements

In 1967, postgraduate student Jocelyn Bell Burnell detected a series of anomalous, highly regular radio signals. Her supervisor initially dismissed the pulses as man-made interference. However, Burnell, who kept analyzing the data meticulously, soon realized that the signals that she recorded were originating from a rapidly spinning neutron star.

Which choice most effectively punctuates the underlined portion of the sentence?

Ancient scholars traveled from all over the Mediterranean to study at the Library of Alexandria. The institution , which housed thousands of papyrus scrolls containing the knowledge of the ancient world, served as the intellectual center of the Hellenistic civilization. Its destruction remains one of the greatest losses in cultural history.

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Organic architecture seeks to promote harmony between human habitation and the natural world. The architect Frank Lloyd Wright, who designed Fallingwater in 1935, revolutionized modern American home design by integrating structures directly into their surroundings. By building the house over a waterfall, he created a masterpiece that seamlessly blended art and nature.

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For decades, art historians debated the authenticity of the Renaissance portrait. The local historian who discovered the forgotten letters, an expert on the artist’s early life recently published a groundbreaking study that resolved the mystery. This publication has sparked renewed interest in the painter's early works.

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During a stormy summer in Switzerland, Mary Shelley began writing her famous novel *Frankenstein*. The young author, who was only eighteen at the time, drew inspiration from conversations about galvanism and scientific discoveries. Today, the book is celebrated as a pioneering masterpiece of science fiction.

Which choice is the correct punctuation for the underlined portion of the sentence?

Before Alan Turing's famous work at Bletchley Park, a team of Polish mathematicians cracked the early military Enigma cipher. Marian Rejewski solved the mathematical equations underlying the machine's rotor permutations. The card catalog that Rejewski compiled during his research, which contained over 100,000 permutations, allowed the team to decrypt messages in minutes.

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Many masterpieces of modernist music premiered in Paris during the early twentieth century. The composition, that Stravinsky wrote for the Ballets Russes, which featured jarring rhythms and dissonant chords, provoked a riot at its premiere. Critics and audiences alike were unprepared for such avant-garde sounds.

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In 1912, Alfred Wegener introduced a revolutionary idea that would reshape our understanding of Earth. Wegener, the meteorologist who proposed the theory of continental drift, faced intense skepticism from his peers. Decades later, the discovery of seafloor spreading finally vindicated his vision.

Which of the following choices is the correct punctuation for the underlined portion of the passage?

In the early twentieth century, German mathematician Emmy Noether proved a theorem that fundamentally linked symmetry and conservation laws. Although her work laid the cornerstone for modern theoretical physics, she initially faced immense institutional barriers due to her gender. The university administration that governed Göttingen, which refused to grant her a formal faculty position allowed her to lecture only under David Hilbert's name.

Which choice best punctuates the underlined portion of the sentence to conform to the conventions of standard written English?

In the mid-twentieth century, researchers mapped the ocean floor using sonar. The maps that Tharp created, which she drafted by hand, proved the existence of the Mid-Atlantic Ridge. This discovery supported the theory of continental drift and revolutionized modern geology.

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In 1943, Jacques Cousteau and Émile Gagnan co-invented a new breathing apparatus for underwater exploration. The Aqua-Lung , which allowed divers to breathe underwater, revolutionized marine research. Scientists could finally observe aquatic life for hours at a time.

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The following passage is an excerpt from a biography of a famous scientist.

In 1962, biologist Rachel Carson published *Silent Spring*, a landmark book that warned of the dangers of chemical pesticides. The book, which initially faced fierce opposition from chemical companies, eventually inspired a nationwide ban on DDT. Her eloquent writing style helped launch the modern environmental movement.

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In the 1940s, geneticist Barbara McClintock studied the inheritance patterns of maize plants. Her research on transposons, which are DNA sequences that can move within a genome, eventually earned her a Nobel Prize in Physiology or Medicine. This groundbreaking work challenged the long-held belief that genes were static entities on chromosomes.

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The following passage contains an underlined portion.

In 1952, British biophysicist Rosalind Franklin captured a groundbreaking X-ray diffraction image of DNA. This photograph, which was known as Photo 51, showed a pattern that was crucial to Watson and Crick’s discovery of the double helix. Today, Franklin is widely recognized for her critical contributions to molecular biology.

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During the Northern Renaissance, painters revolutionized the medium of panel painting by experimenting with new binders. Artists who adopted oil-based pigments, which dried much slower than traditional egg tempera achieved unprecedented levels of detail and luminosity. This technical shift allowed for the realistic depiction of light and texture that defined the era.

Which of the following options correctly punctuates the underlined portion of the sentence?

The document <u>that contains the signature, which was drafted in $1776$,</u> is preserved in the national archives. It is displayed under protective glass to prevent fading.

Which choice is the correct punctuation for the underlined portion of the sentence?

During the Islamic Golden Age, scholars made significant strides in understanding the behavior of light. The physicist Ibn al-Haytham , who is often considered the father of modern optics, revolutionized scientific methodology through his rigorous experiments. In his influential work *Book of Optics*, he demonstrated that light travels in straight lines and enters the eye to produce vision.

Which choice best punctuates the underlined portion of the sentence?

For centuries, the intricate carvings on Mayan monuments remained an undeciphered mystery. In the late twentieth century, art historian Linda Schele, who studied the glyphs, that were carved on the temple, made a breakthrough by translating the history of Palenque. Her work revealed that the carvings were not mere symbols but a rich record of historical events.

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The deep-sea explorer Sylvia Earle has spent her career advocating for the protection of marine ecosystems. The sustainable marine sanctuaries that Earle has helped establish, which she refers to as "hope spots," have prompted international conservation efforts. These protected areas serve as critical refuges for threatened species.

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The library features a special collection of classic literature. The novel that Mary Shelley wrote, which became a bestseller, is displayed in a glass case. Visitors can view the original manuscript and hand-drawn illustrations.

Which of the following is the correct punctuation for the underlined portion of the sentence?