Punctuation of Nonessential Elements

The following passage is about the American architect Julia Morgan. Which punctuation mark correctly completes the passage by setting off the nonessential relative clause?

During the Italian Renaissance, the pigment ultramarine was highly prized by master painters for its exceptionally vivid blue hue. Derived from the semi-precious stone lapis lazuli _______ imported from remote mines in the historical region of Badakhshan, the pigment was so costly to obtain that artists reserved it almost exclusively for depicting the robes of important figures.

Which choice completes the text so that it conforms to the conventions of Standard English?

Read the passage below. What punctuation mark should be placed in the blank to correctly set off the nonessential element?

In 1915, amateur astronomer George Willis Ritchey designed a reflecting telescope that utilized a hyperbolic primary mirror to eliminate spherical aberration. This innovative configuration ______ represented a monumental leap forward in optical engineering, though it remained largely unappreciated until the launch of the Hubble Space Telescope decades later.

Which choice completes the text so that it conforms to the conventions of Standard English?

Complete the passage by writing the appropriate punctuation mark(s) in the blank to set off the nonessential element.

In 1915, amateur astronomer George Willis Ritchey designed a new type of reflecting telescope that utilized a hyperbolic primary mirror. This innovative configuration ______ eliminated the optical aberration known as coma, which had long plagued traditional Newtonian reflectors and limited the clarity of deep-sky astrophotography. Today, nearly all major research installations, including the Hubble Space Telescope, rely on this design to capture high-resolution images of distant galaxies.

Which choice completes the text so that it conforms to the conventions of Standard English?

In 2006, the International Astronomical Union officially reclassified Pluto as a dwarf planet. This decision ______ sparked widespread debate among scientists and the public alike, many of whom had grown fond of the distant icy world. Ultimately, the reclassification helped astronomers establish a clearer definition for what constitutes a true planet in our solar system.

Which choice completes the text with the most logical and grammatically correct punctuation?

The giant squid (*Architeuthis dux*) has long captivated researchers, but its deep-sea habitat makes direct observation extremely difficult. In 2004, Japanese marine biologists captured the first active images of a live giant squid in its natural environment. This historic achievement ______ helped scientists understand the predatory behaviors of this elusive creature.

Which choice completes the text so that it conforms to the conventions of Standard English?

The following passage is an excerpt from an art history essay. Complete the passage by typing the punctuation mark that correctly fills the blank to ensure standard English conventions.

The following passage is from an academic text about South American archaeology. Complete the passage by entering the single punctuation mark that should go in the blank to correctly set off the nonessential element.

The following passage is an excerpt from an academic text on astrobiology. The second sentence contains a nonessential appositive phrase. What punctuation mark should be inserted into the blank to correctly set off this phrase?

During her research in the 1940s, geneticist Barbara McClintock made a revolutionary discovery while studying maize chromosomes. McClintock identified transposons ______ which challenged the prevailing scientific belief that genomes are static. Her pioneering work eventually earned her the Nobel Prize in Physiology or Medicine in 1983.

Which choice completes the text so that it conforms to the conventions of Standard English?

In 1972, French analysts at the Pierrelatte uranium enrichment plant discovered a bizarre anomaly in uranium samples from Gabon. The proportion of the fissile isotope uranium-235 was significantly lower than the standard value found everywhere else on Earth. Further investigation revealed that the Oklo deposits ______ had actually undergone self-sustaining nuclear fission reactions approximately two billion years ago.

Which choice completes the text so that it conforms to the conventions of Standard English?

In 1967, astrophysicist Jocelyn Bell Burnell detected a series of regularly spaced radio pulses while analyzing data from a newly constructed radio telescope. Initially, some researchers hypothesized that the signals were artificial transmissions from an extraterrestrial civilization. However, this anomaly ______ ultimately proved to be the first discovered pulsar, a highly magnetized rotating neutron star.

Which choice completes the text so that it conforms to the conventions of Standard English?

In 1915, chemist Alice Ball pioneered a groundbreaking technique to make chaulmoogra oil injectable, offering hope to thousands of leprosy patients. Her innovative process ______ involved chemically modifying the oil's fatty acids so they could be easily dissolved in water and absorbed by the human body.

Which choice completes the text so that it conforms to the conventions of Standard English?

The passage below contains a nonessential clause set off by punctuation. What punctuation mark should be typed in the blank to correctly complete the sentence?

Observations from the New Horizons spacecraft have revolutionized our understanding of the Kuiper belt, a region of icy bodies beyond Neptune. Among the most surprising findings is the geological complexity of the dwarf planet Pluto, which [blank] boasts vast plains of nitrogen ice and towering mountains of water ice.

Which choice completes the text so that it conforms to the conventions of Standard English?

The passage below contains a blank indicating a missing punctuation mark. Which punctuation mark should be placed in the blank to correctly set off the nonessential element?

The mimic octopus ______ possesses an extraordinary ability to impersonate other marine species. By dynamically altering its shape, color, and movement, this clever cephalopod can mimic creatures such as flatfish, lionfish, and sea snakes. Marine biologists have observed that the animal adjusts its behavior depending on the specific threat it faces, demonstrating an impressive level of situational awareness.

Which choice completes the text so that it conforms to the conventions of Standard English?

The passage below contains a blank indicating a missing punctuation mark. Which punctuation mark should be placed in the blank to correctly set off the nonessential relative clause?