5/16/26
When Paige Embry, author of Our Native Bees: North America’s Endangered Pollinators and the Fight to Save Them, learned that bees extract pollen from flowers by shaking them, she embarked on a reporting journey to document the lives of North America’s 4,000 wild native pollinators. Some secrete silk, she discovered, while others shave fuzzy plants to build plush pillows for their eggs. Still others nest in rose stems, cow patties, or snail shells.
A. NO CHANGE
B. them. She embarked
C. them, and she embarked
D. them, she embarked,
Click here for the answer.
5/14/26
In recent years, scientists have become increasingly aware that plants thrive through cooperation rather than competition. For example, oaks that are subjected to drought conditions have been shown to provide nutrition to their beneficial partners by transferring water from their tap roots up through their root systems to associated fungal networks, nourishing these beneficial partners. In fact, some researchers believe that such networks are the principal way that plants extract nutrients from the soil.
A. NO CHANGE
B. providing nourishment for these beneficial partners.
C. sustaining these beneficial partners.
D. DELETE the underlined portion (replacing the comma after networks with a period).
Click here for the answer.
5/13/26
When I was a child growing up on the Eastern Shore of Maryland, crossing a big bridge meant facing unexpected challenges. The majestic Chesapeake Bay Bridge was my family’s main route off of the rural shore and towards “real cities,” where we could walk among crowds and shop in stores unlike anything we had at home. But these trips were also journeys in themselves— a chance to spot bottlenose dolphins and peregrine falcons and to see both our home and our destination from a new perspective.
Which choice best introduces the topic of the paragraph?
A. NO CHANGE
B. taking a step toward independence.
C. entering a portal to a new world.
D. returning to my roots.
Click here for the answer.
5/12/26
Although it is estimated that 10 meteorites come crashing to Earth from outer space every day, researchers only discover a few of these rocks each year. They are easiest to spot when they fall on relatively stable geographic environments, making it unnecessary for search teams to use metal detectors like the Arizona desert.
A. NO CHANGE
B. environments that make it unnecessary for search teams to use metal detectors like the Arizona desert.
C. environments like the Arizona desert, making it unnecessary for search teams to use metal detectors.
D. environments like metal detectors that make it unnecessary for search teams in the Arizona desert.
Click here for the answer.
5/11/26
In 1997, David Perry founded Indigo Ag, a company dedicated to commercializing microorganisms that help plants grow. Indigo Ag’s scientists have identified a variety of microbes that confer resistance to drought, are developing others that reduce the need for chemical fertilizers and pesticides in five important crops: corn, rice, soybeans, cotton, and wheat.
A. NO CHANGE
B. scientists identify
C. scientists, having identified
D. scientists identified
Click here for the answer.
5/10/26
In the past few years, governments have begun to see automation as the key to better urban futures. Many cities are becoming test-beds for experiments with robots in social spaces, where robots have both a practical purpose (for which they are programmed) and a symbolic role (to demonstrate good city governance). Whether through autonomous cars, automated pharmacists, service robots in local stores, or autonomous drones delivering parcels, cities are being automated at a steady pace.
Which choice provides an example that is most similar to the other example in the sentence?
A. NO CHANGE
B. (to facilitate everyday life)
C. (they come in many shapes and sizes)
D. (and are becoming ever more intelligent)
Click here for the answer.
5/9/26
Today, humans can live in space for months at a time, and some space travelers are lucky enough to visit the realm of microgravity more than once. Repeat trips into space teach astronauts not only to survive in a hostile and alien environment but also adjusting to life back on Earth.
A. NO CHANGE
B. they adjust
C. adjusted
D. to adjust
Click here for the answer.
5/8/26
The “Green Revolution”—championed by American agronomist Norman Borlaug, who was awarded the Nobel Peace Prize in 1970 for his work—led farmers to: increase their use of chemical fertilizers, adopt high-yielding crop varieties, and improve their irrigation practices and technologies. Today, those practices are firmly entrenched aspects of industrial agriculture.
A. NO CHANGE
B. to increase their use of chemical fertilizers;
C. to increase their use of chemical fertilizers,
D. to increase their use, of chemical fertilizers
Click here for the answer.
5/7/26
In the never-ending symphony of the sea, there’s a standout among the percussive pings of bottlenose dolphins and the plaintive calls of humpback whales. Recordings of bowhead whales show that these mammals sing intricate yet varied songs—they’re more like jazz musicians than Beethoven or Bach.
A. NO CHANGE
B. intricate, yet varied
C. intricate yet, varied
D. intricate yet varied,
Click here for the answer.
5/6/26
The largest pyramid, built for the Pharaoh Khufu around 2530 B.C. and intended in lasting an eternity, was until fairly recently the largest building on the planet. To raise it, laborers moved six-and-a-half million tons of stone—some in blocks as large as nine tons—into position using nothing but wood and rope.
A. NO CHANGE
B. on lasting
C. for lasting
D. to last
Click here for the answer.
5/5/26
Numerous factors—from changes in air temperature to the tug of nearby storms—can affect a tornado’s development. Unlike hurricanes, which can be spotted days off shore, tornadoes develop over the course of hours or minutes, which makes taking on-the-ground measurements even more challenging.
A. NO CHANGE
B. affect a tornadoes development.
C. effect a tornado’s development.
D. effect a tornadoes development.
Click here for the answer.
5/4/26
The cognitive scientist Rafael Núñez of the University of California at San Diego doesn’t buy the conventional wisdom that people have a naturally innate capacity for understanding numbers. Rather, he thinks that “number sense” is a product of culture, like writing and architecture.
A. NO CHANGE
B. a natural and innate
C. a natural, innate
D. an innate
Click here for the answer.
5/3/26
The emperors of the Tang Dynasty (618 – 907 AD) are believed to have been the first to eat a frozen, milky confection. This early version of ice cream was made with cow, goat, or buffalo milk that was heated with flour. Camphor, an aromatic substance harvested from evergreen trees, was added to enhance the texture and flavor. Subsequently, the mixture was placed into metal tubes and lowered into an icy pool until frozen.
A. NO CHANGE
B. Nevertheless,
C. Thus,
D. Despite this,
Click here for the answer.
5/2/26
Despite the economic promises touted by supporters of the Golden Gate Bridge, the project met fierce resistance from an array of business and civic leaders. Not only would the bridge impede the shipping industry and mar the bay’s natural beauty, they argued, it wouldn’t survive a trembler like the San Francisco Earthquake that crippled the city in 1906.
A. NO CHANGE
B. it also won’t survive
C. and it also wouldn’t survive
D. but it also wouldn’t survive
Click here for the answer.
5/1/26
Before I started working on real-world robots, I wrote about their fictional and historical ancestors. That wasn’t too different from what I do now. In factories, labs, and of course science fiction, robots continue to fuel our imaginations about artificial humans and smart machines.
Which of the following would NOT be an acceptable alternative to the underlined word?
A. nourish
B. fire
C. supply
D. stimulate
Click here for the answer.
4/30/26
A beetle’s wings are rarely visible. Hidden behind armored shields on the creature’s back and unfolding in whirring sheets, whisking their clumsy owners away from danger.
A. NO CHANGE
B. back, they unfold
C. back to unfold
D. back and unfold
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4/29/26
In the first half of the twentieth century, tornadoes were said so unpredictable that in order to prevent mass hysteria, the word “tornado” was forbidden from weather forecasts. Progress on the forecasting front moved slowly until the 1970s, when the first Doppler radar allowed scientists to track a storm’s development and spot the signs of a developing twister.
A. NO CHANGE
B. considered
C. viewed
D. described
Click here for the answer.
4/28/26
The correlation between bad moods and negative judgments allows people to make informed guesses about how others are feeling by observing their actions and choices.
A. NO CHANGE
B. judgments allow
C. judgments have allowed
D. judgments, which allow
Click here for the answer.
4/27/26
The original Shinkansen, or bullet train, connects the largest Japanese cities of Tokyo and Osaka, is the world’s busiest high-speed rail line. Carrying 151 million passengers per year, it has transported more travelers than any other high-speed line in the world.
A. NO CHANGE
B. train connects
C. train connects:
D. train, which connects
Click here for the answer.
4/26/26
In the mid-nineteenth century, the Oregon Trail was the principle pathway for immigrants seeking land and opportunity on the American frontier. From its main departure points in Missouri, the grueling overland route stretched 2,000 miles over the Great Plains and the Continental Divide, finally ending in the fertile Willamette Valley or the gold fields of California.
A. NO CHANGE
B. principal pathway for
C. principle pathway to
D. principal pathway to
Click here for the answer.
4/25/26
A snowflake begins to form when an extremely cold water droplet freezes onto a pollen or dust particle in the sky, this creates an ice crystal. As the ice crystal falls to the ground, water vapor freezes onto the primary crystal, building new crystals—the six arms of the snowflake.
A. NO CHANGE
B. sky and create
C. sky, creating
D. sky; creating
Click here for the answer.
4/24/26
Not so long ago, astronomers didn’t know if there were planets outside our solar system or, if there were, whether it could ever be found. But starting with the 1995 discovery of a planet circling the sun-like star 51 Pegasi, there has been a revolution.
A. NO CHANGE
B. this
C. they
D. DELETE the underlined word.
Click here for the answer.
4/23/26
In recent years, robotics has found its way into our everyday lives, changing them in fundamental ways. Designers have a central role to play in this process, which they shape the interfaces between humans and machines.
A. NO CHANGE
B. process:
C. process,
D. process that
Click here for the answer.
4/22/26
Researchers at the University of Maryland have developed a super-lightweight insulating material that, they claim, could prove to be a superior alternative to styrofoam. The material, made from tiny wood fibers, is called nanowood.
A. NO CHANGE
B. material, that they
C. material that they
D. material and they
Click here for the answer.
4/21/26
Hummingbirds have long intrigued scientists. Their wings can beat 80 times a second, and their hearts can beat more than 1,000 times a minute. They consume nothing but nectar—a sugar- and nutrient-rich liquid produced by plants—they are capable of packing on 40 percent of their body weight in fat for migration.
A. NO CHANGE
B. Because they
C. Although they
D. Since they
Click here for the answer.
4/20/26
The Megalodon, a prehistoric ancestor of the modern shark, had a bite force of 12 to 20 tons, somewhere between six and ten times stronger than a modern Great White.
A. NO CHANGE
B. then a modern Great White.
C. than that of a modern Great White.
D. than those of a modern Great White.
Click here for the answer.
4/19/26
Steve Desch, an astrophysicist at the University of Arizona, can see the future of exoplanet research, and it’s not pretty. Imagine, he says, that astronomers use NASA’s upcoming James Webb Space Telescope to scour the atmosphere of an Earth-mass world for signs of life. They might chase hints of atmospheric oxygen for years before realizing they were false positives produced by geological activity instead of living things.
As it is used in the passage, “scour” most nearly means
A. cleanse
B. consume
C. search
D. burnish
Click here for the answer.
4/18/26
With the car windows down on the first warm day of spring, the urge is unshakable. You extend your arm into the wind, tracing the city skyline in a natural motion somewhere between swimming and waving. As you move your hand, altering the flow of the air. The redirected air in turn exerts a force on your hand.
A. NO CHANGE
B. hand and alter
C. hand, you alter
D. hand to alter
Click here for the answer.
4/17/26
Although the concept of sleep-learning, also referred to as hypnopaedia, has been discredited, neuroscientists are now discovering ways to use stimuli such as sound cues during sleep to strengthen peoples’ memories.
A. NO CHANGE
B. peoples memories’.
C. people’s memories.
D. people’s memory’s.
Click here for the answer.
4/16/26
Once upon a time, it seems that Mars had oceans. However, the exact appearance of these bodies of surface water is a matter of intense debate. Most evidence points towards the deep past, some 4 billion years ago, as the age where Mars could have held marine environments. Since then, the red planet has most likely been cold and arid, with only the occasional shift of climate conditions.
A. NO CHANGE
B. in which
C. which
D. in that
Click here for the answer.
4/15/26
Baseball has a long and rich history in Japanese-American diplomacy. After the sport was introduced to Japan in the 1870s by the American educator Horace Wilson, it became an important part of Japanese popular culture. Over time, baseball has served as a unifier, bringing together the people of two nations with very different histories and cultures.
A. NO CHANGE
B. educator, Horace Wilson
C. educator, Horace Wilson,
D. educator Horace Wilson
Click here for the answer.
4/14/26
One of the most renowned architects of the twentieth century, Frank Lloyd Wright was the pioneer of the Prairie School movement and he developed the Usonian home, his unique vision for urban planning in the United States.
A. NO CHANGE
B. and developing
C. the developer of
D. had developed
Click here for the answer.
4/13/26
In terms of intelligence, the octopus stands far above most other animals. During one really cool study, researchers tested whether this creature is able to distinguish between different people. Two individuals interacted with an octopus, with one acting extremely friendly and another seeming cold and standoffish. Later, when the two people entered the octopus’s living area, the octopus ignored the impersonal one in favor of the friendlier guest.
A. NO CHANGE
B. awesome
C. intriguing
D. totally neat
Click here for the answer.
4/12/26
In the early days of mariachi music, players dressed informally. With increased employment opportunities and more formal presentations, however, uniforms became common. When mariachis first acquired the purchasing power to dress their groups in uniforms, the apparel they had chose most often was the charro suit, which consisted of fitted trousers, a short jacket, and an embroidered belt.
A. NO CHANGE
B. have chosen
C. chose
D. choose
Click here for the answer.
4/11/26
You can probably recall a situation, in sports or otherwise, in which you felt like you had momentum on your side: your body was in sync, your mind was focused, and you had a high level of confidence. In these moments of flow, success feels inevitable, and effortless.
A. NO CHANGE
B. you had a high confidence level.
C. your high confidence level.
D. your level of confidence was high.
Click here for the answer.
4/10/26
Despite decades of research, the sun remains an enigma. Every 11 years or so its activity spikes, creating flares and coronal mass ejections—the plasma-spewing eruptions that shower Earth with charged particles and beautiful auroral displays. Then, however, the so-called solar maximum fades toward solar minimum, and the sun’s surface grows eerie quiet.
A. NO CHANGE
B. eerily quiet.
C. eerie quietly.
D. eerily quietly.
Click here for the answer.
4/9/26
According to research, people are generally biased toward believing that information is true. (After all, most things that we read or hear are true.) In fact, there’s some evidence that we initially process all statements as true and that cognitive effort is required to mentally mark some of them as false.
In the last sentence, the word “mark” most nearly means
A. distort
B. label
C. transmit
D. inscribe
Click here for the answer.
4/8/26
It has taken a while for scientists to piece together the riddle of just when and where cats first became domesticated. In many cases, this type of question can be easily answered by the archaeological record, but in this instance the matter is complicated by the fact that wild cats and domesticated cats have remarkably similar skeletons.
All of the following placements for the underlined word would be acceptable EXCEPT
A. where it is now.
B. after the word can.
C. after the word answered.
D. after the word the.
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4/7/26
Knowing that an employee demonstrates high levels of conscientiousness won’t tell you whether his or her work will be careful or sloppy if you inspect it at a particular moment. But if a large company hires hundreds of employees which are all conscientious, this strategy will likely pay off with a small but consistent average increase in careful work.
A. NO CHANGE
B. who
C. whom
D. DELETE the underlined word.
Click here for the answer.
4/6/26
Growing hardy and plentiful on short, stout bushes, the prairie cherry’s ornamental blooms and glossy leaves produce a deep-red fruit that is less sweet than the traditional cherry, and can be eaten straight from the tree.
A. NO CHANGE
B. cherry, and can be eaten straight,
C. cherry and can be eaten straight
D. cherry and can be eaten straight,
Click here for the answer.
4/5/26
During the early days of space travel, astronauts squeezed most of their meals out of tubes. A sugary, orange-flavored drink, sold commercially as Tang, was considered a tasty treat. Food was fuel, and little more. Meals are stored in locker trays held by a net so they won’t float away. In fact astronauts can dine on a variety of freeze-dried meals using regular forks and spoons. And, for a few years, crews in the International Space Station (ISS) have been able to savor a taste of food that’s actually fresh.
Which of the following provides the best transition between the previous sentence and the sentence that follows?
A. NO CHANGE.
B. Salt and pepper are available, but only in liquid form.
C. Today, eating in space has become much less of a chore.
D. Being in space can put a damper on an astronaut’s appetite.
Click here for the answer.
4/4/26
Fraudulent images have been around for as long as photography itself, but Photoshop ushered image doctoring into the digital age. Now, artificial intelligence is poised to take photographic fakery to a new level of sophistication thanks to artificial neural networks who’s algorithms can analyze millions of pictures of real people and places and use them to create convincing fictional ones.
A. NO CHANGE
B. who’s algorithms’
C. whose algorithm’s
D. whose algorithms
Click here for the answer.
4/3/26
The human eye may seem capable of taking in a lot of information, but in reality it can focus on only a thumbnail-sized area of vision—the brain fills in the rest. Furthermore, peripheral vision provides less details than central vision does, conveying images at a much lower resolution.
A. NO CHANGE
B. less details then
C. fewer details than
D. fewer details as
Click here for the answer.
4/2/26
When trying to learn new material, you might assume that the more work you put in, the better you will perform. Yet taking the occasional down time – to do literally nothing – may be exactly what you need. Dimming the lights, sitting back, and enjoying a few moments of quality contemplation will help one retain the information much more effectively.
A. NO CHANGE
B. us
C. you
D. them
Click here for the answer.
4/1/26
Kagome baskets are characterized by a symmetrical pattern of interlaced triangles. A pattern that has preoccupied physicists for decades.
A. NO CHANGE
B. triangles, it is a pattern
C. triangles—a pattern
D. triangles; a pattern
Click here for the answer.
3/31/26
Research suggests that it is possible to cultivate insight by adjusting external conditions. For example, studies show that open surroundings, including high ceilings and tall windows, can broaden one’s perspective. Low ceilings, narrow corridors, and windowless offices have the opposite effect.
Which of the following would be the LEAST acceptable alternative to the underlined word?
A. enlarge
B. raise
C. expand
D. widen
Click here for the answer.
3/30/26
Robert Wright, the founder of the website Mindful Resistance, claims that meditation, if widely practiced, can help people overcome aggression and other harmful behaviors. Not only does meditation make us happier, Wright says but it also makes us kinder, less selfish, and more considerate of others.
A. NO CHANGE
B. Wright says; but it
C. Wright says, but
D. Wright says, it
Click here for the answer.
3/29/26
The Transiting Exoplanet Survey Satellite, or TESS, is the latest effort to try to answer questions that dominate astronomy for the last several decades: Are we alone? Are there other Earths? Evidence of even a single microbe anywhere else in the galaxy would fundamentally change science.
A. NO CHANGE
B. are dominating
C. have dominated
D. dominated
Click here for the answer.
3/28/26
For a robot to help scientists truly understand marine life, it must engage with underwater environments without disturbing them. An agile robotic fish created by Massachusetts Institute of Technology researchers does just that. Indeed, it has been observed interacting peacefully with aquatic life along coral reefs in the Pacific Ocean at depths of up to 18 meters.
A. NO CHANGE
B. However,
C. On the other hand,
D. Therefore,
Click here for the answer.
3/27/26
Whereas the tips of most icebergs are covered in densely packed snow or have been weathered by the elements a few rare ones are free of debris and expose glassy, aqua-green ice with water flowing through it.
A. NO CHANGE
B. elements, a few
C. elements; a few
D. elements, and a few
Click here for the answer.
3/26/26
The seeds of the Theobroma cacao tree have, over hundreds of years, been linked to therapies for more than 100 diseases and conditions. Its status as a cure-all dates back over 2,000 years.
A. NO CHANGE
B. It’s
C. Their
D. They’re
Click here for the answer.
3/25/26
In July of 1848, a group of men and women gathered in Seneca Falls, New York, for the first women’s rights convention held in the United States. Many important figures of the day attended, and among them were: Elizabeth Cady Stanton, Lucretia Mott, and Frederick Douglass.
A. NO CHANGE
B. were—Elizabeth Cady Stanton, Lucretia Mott
C. were Elizabeth Cady Stanton, Lucretia Mott,
D. were Elizabeth Cady Stanton; Lucretia Mott,
Click here for the answer.
3/24/26
In 1927, Charles Lindbergh earned instantaneous fame for becoming the first person to fly solo across the Atlantic. In 1925, however, he was an obscure Air Mail pilot, where he was responsible for transporting packages between Chicago and St. Louis.
A. NO CHANGE
B. pilot. Who was responsible
C. pilot, he was responsible
D. pilot responsible
Click here for the answer.
3/23/26
Many of us listen to music as a way to calm or energize ourselves. Mona Lisa Chanda and Daniel Levitin, professors at McGill University, have had a look at more than 400 scientific papers on the neurochemical effects of music. Their conclusion was that music truly can boost the body’s immune system, reduce anxiety, and regulate people’s moods.
A. NO CHANGE
B. checked out
C. examined
D. overlooked
Click here for the answer.
3/22/26
Killer whales are known to live in groups that have unique vocal “dialects” in the wild, they may also copy sounds made by other members of their species, although that ability has not yet been seriously studied.
A. NO CHANGE
B. dialects. In
C. dialect, in
D. dialects; and in
Click here for the answer.
3/21/26
Standard computer processors rely on packets, or bits of information: each of the packets represents a single yes or no answer. Quantum processors, on the other hand, don’t work in the realm of yes or no but rather operating in the almost surreal world of yes and no.
A. NO CHANGE
B. would operate
C. operated
D. operate
Click here for the answer.
3/20/26
Although robots have been used in factories for decades, getting them to leave the shop-floor has been no easy task. In manufacturing plants, they carry out pre-ordained, repetitive tasks all day and night. But if they step outside, they are unable to deal with the chaos of the real world, where order and routine are gone. Even the simplest tasks are complicated by the sensors and wires that must follow them around.
Given that all of the choices are true, which one best concludes the paragraph and reaffirms the idea that the real world is disorderly?
A. NO CHANGE
B. unpredictability and vagueness of human interaction.
C. difficulties of creating robots of different sizes.
D. limited amount of energy provided by batteries.
Click here for the answer.
3/19/26
Reading foreign books and watching international television are recommended to be a way for people to improve their knowledge of world affairs, but neither is a substitute for spending time in another country.
A. NO CHANGE
B. to be ways
C. as a way
D. as ways
Click here for the answer.
3/18/26
Sometimes a symbol can be so familiar that even out of context—different surroundings, different colors and very different materials—it remains immediately recognizable. That’s the case for the five neon-colored tipis that anchor the exhibition “Manifestipi.” Created by ITWE Collective, a trio of artists based in Winnipeg and Montreal, the eight-foot-tall structures made of frosted plexiglass are unmistakeably tipis. Although they look nothing like traditional ones.
A. NO CHANGE
B. Montreal, and the eight-foot tall structures made of frosted plexiglass are unmistakeably tipis, although
C. Montreal the eight-foot tall structures, made of frosted plexiglass are unmistakeably tipis, although
D. Montreal, the eight-foot tall structures made of frosted plexiglass are unmistakeably tipis, although
Click here for the answer.
3/17/26
Many Parisians hated the Eiffel Tower when it was first erected in 1889. Although they may seem incomprehensible now, that sentiment is perhaps more understandable when you consider that the monument was originally painted red.
A. NO CHANGE
B. it
C. one
D. these
Click here for the answer.
3/16/26
Astronomers conducting a galactic census of planets in the Milky Way now suspect most of the universe’s habitable real estate exists on worlds orbiting red dwarf stars, which are smaller but far more numerous than stars like our Sun.
A. NO CHANGE
B. then stars
C. than that of stars
D. as stars
Click here for the answer.
3/15/26
Often advertised to promote health and reduce stress, some doctors warn that dietary supplements can have harmful effects, even though they are easy to purchase.
A. NO CHANGE
B. it is easy to purchase dietary supplements, but some doctors warn that they can have harmful effects.
C. dietary supplements are easy to purchase, yet some doctors warn they can have harmful effects.
D. harmful effects can be had by dietary supplements, even though they are easy to purchase, some doctors warn.
Click here for the answer.
3/14/26
From his desk at the European Space Operations Centre in Darmstadt, Germany, space debris analyst Tim Flohrer keeps track of the 23,000 or so catalogued objects currently orbiting the Earth. These objects range from spacecraft and satellites – some working, most not – to rocket parts that they have discarded.
A. NO CHANGE
B. one has
C. we have
D. space agencies have
Click here for the answer.
3/13/26
Whatever its origins, brunch seems to have caught on in the United States during the 1930s, supposedly because Hollywood stars whom made transcontinental train trips frequently stopped off in Chicago to enjoy a late morning meal.
A. NO CHANGE
B. who
C. which
D. DELETE the underlined word.
Click here for the answer.
3/12/26
The Sahara has not always been a wilderness of sand dunes. German climatologists Rudolph Kuper and Stefan Kröpelin, analyzed the radiocarbon dates of archaeological sites, recently concluded that the region’s prevailing climate pattern changed around 8,500 B.C., with the monsoon rains that covered the tropics moving north.
A. NO CHANGE
B. Kröpelin analyzed
C. Kröpelin, they analyzed
D. Kröpelin, who analyzed
Click here for the answer.
3/11/26
When researchers first found Angamuco, an ancient city in western Mexico built by rivals of the Aztecs, they tried several methods to explore the site, including an on-the-ground approach. Although this strategy compiled a finding of impressive architectural features, they quickly realized it would take them a decade to survey the entire area. As a result, they turned to a laser mapping technique known as light detection and ranging, or LiDAR scanning.
A. NO CHANGE
B. halted
C. yielded
D. adapted
Click here for the answer.
3/10/26
Until the early 1970s, most consumers knew very little about the nutritional content of the prepared foods they purchased. Around that time, however, the dramatic growth in processed food lead to a system of both voluntary and mandatory nutrition labeling.
A. NO CHANGE
B. leads
C. led
D. has lead
Click here for the answer.
3/9/26
Although models of planet-forming disks suggest that most star systems should, like the eight planets of our solar system, have roughly circular orbits, in reality, however, only about one-third of the planets identified in other solar systems orbit in a circular fashion.
A. NO CHANGE
B. but in reality,
C. and in reality,
D. in reality,
Click here for the answer.
3/8/26
Vocal imitation is a hallmark of human spoken language, yet in other animals it is strikingly rare. Dolphins and beluga whales are among the few mammals that can copy sounds from other species or each other. A small number of animals can also imitate human speech, like parrots are the most famous example, but some members of the crow family are able to do so as well.
A. NO CHANGE
B. speech such as parrots
C. speech: parrots
D. speech, parrots
Click here for the answer.
3/7/26
Dogs and humans may be the best of friends today, but research on ancient canine remains shows that the relationship didn’t develop overnight. For long periods of time, people lived in tension with their canine companions. Theirs was a relationship of necessity as well as being convenient.
A. NO CHANGE
B. as well as convenience.
C. and it was convenient.
D. and having convenience too.
Click here for the answer.
3/6/26
Mushrooms are everywhere — on forest floors, in gardens, and in networks connecting below our feet. The largest organism on Earth is actually a honey mushroom, an underground web, that covers more than 3.7 square miles in Oregon’s Blue Mountains.
A. NO CHANGE
B. web that, covers
C. web covers
D. web covering
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3/5/26
While doctors are increasingly dependent on computers, they can also use these devices to help patients in new and important ways. Therefore, electronic medical records can help physicians share information and keep reliable records about which medications a person has been prescribed over a long period of time.
A. NO CHANGE
B. for instance,
C. however,
D. meanwhile,
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3/4/26
Spiders are among the hardiest creatures in existence: these eight-legged insects live on every continent other than Antarctica and are established in nearly every habitat on Earth, excepting the air and the sea.
A. NO CHANGE
B. exempting
C. to exempt
D. with the exception of
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3/3/26
A lack of genetic diversity has proven disastrous to many commercial crops. For example, nearly all bananas for sale today are clones of a single parent plant called the Cavendish, initially bred in Great Britain during the nineteenth century. Although Cavendish bananas are hardier than other types of bananas, they are also less flavorful.
A. NO CHANGE
B. Cavendish; initially bred
C. Cavendish: initially bred
D. Cavendish, initially being bred
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3/2/26
From the mechanical humanoids in the 1927 film, Metropolis, to the sinister computer in Stanley Kubrick’s 2001 – A Space Odyssey (1968), movie robots have played a crucial role in shaping people’s attitudes toward these machines for decades.
A. NO CHANGE
B. film, Metropolis
C. film Metropolis,
D. film Metropolis
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3/1/26
The origins of meteorology, or the study of the weather, date back centuries: members of the first agricultural settlements predicted floods based on annual cycles, and inscriptions on ancient tablets referred to different seasons. It was not until just a few hundred years ago, however, that technology became sufficiently advanced to permit any real breakthroughs.
Which choice provides the most relevant and specific information?
A. NO CHANGE
B. noted the connection between thunder and rain.
C. were made with simple tools.
D. described a variety of plants and animals.
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2/28/26
Researchers have long believed that planets form in the disc of gas and dust encircling a young star, but the discovery of planets that are very different from our own may have the potential of turning this theory of solar system formation upside down.
A. NO CHANGE
B. in turning
C. for turning
D. to turn
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2/27/26
Bar-tailed godwits have migrated 6,000 miles from Alaska to New Zealand for thousands of years, but a clear picture of their travels have emerged only recently. Today, researchers are beginning to uncover the secrets behind these birds’ remarkable journeys.
A. NO CHANGE
B. has emerged
C. emerge
D. emerging
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2/26/26
Take a look at some of the flowers photographed by Carol Sharp, and you might feel as if you’ve suddenly been transported into an alien world. In Sharps’ pictures, pigmented petals contrast starkly with a black background, while specks of light scatter across the blossoms.
A. NO CHANGE
B. Sharp’s
C. Sharps’s
D. Sharps
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2/25/26
Formed by volatile chemical compounds that rapidly disintegrate, odors are often fleeting and rapidly disappear, remaining only in people’s memories.
A. NO CHANGE
B. fleeting, disappearing rapidly,
C. fleeting so that they disappear rapidly,
D. fleeting,
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2/24/26
In 1610, the year Galileo began viewing the sky through the lens of a telescope, he had become the first person to observe Saturn’s rings directly.
A. NO CHANGE
B. has become
C. would become
D. became
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2/23/26
Because fairs often attracted large and uncontrollable crowds, permission to hold one could only be granted by royal charter during the Middle Ages.
(A) NO CHANGE
(B) Because they often attracted large and uncontrollable crowds, permission to hold a fair could only be granted by royal charter during the Middle Ages.
(C) Having often attracted large and uncontrollable crowds, it could only be permitted for a fair to be held by royal charter during the Middle Ages.
(D) Often attracting large and uncontrollable crowds, during the Middle Ages fairs could only be permitted by royal charter.
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2/22/26
In the last few years, some towns in Iceland, India and China have experimented with “floating” cross walks. They rely on three-dimensional optical illusions for their effectiveness, they make the crossings appear to be floating above the ground, thus causing drivers to slow down.
A. NO CHANGE
B. Relying on
C. These rely on
D. Although they rely on
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2/21/26
If you had stepped off a plane in Bogota, Colombia, in the 1960s, one of the first things you would of probably saw outside the airport was a giant billboard. In a slightly menacing tone, it said, “Coffee rust is the enemy. Don’t bring plant materials from abroad.”
A. NO CHANGE
B. would of probably seen
C. would have probably saw
D. would have probably seen
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2/20/26
Enabling workers as well as pedestrians to walk in climate-controlled comfort even when temperatures drop well below zero, and the Minneapolis Skyway System is an interlinked collection of enclosed footbridges that connect various buildings over 11 miles of downtown Minneapolis.
A. NO CHANGE
B. zero, but the Minneapolis Skyway System
C. zero, the Minneapolis Skyway System, which
D. zero, the Minneapolis Skyway System
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2/19/26
Cheetahs are known for their impressive running speeds, which can reach more than 60 miles per hour. Lions are more powerful. However, they are not nearly as fast on their feet.
Which of the following would NOT be an acceptable alternative to the underlined portion?
A. powerful, but they are
B. powerful; they are, however,
C. powerful but
D. powerful, but are
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2/18/26
The “Ring of Fire” is a string of volcanoes, earthquake sites, and tectonic plates around the Pacific. It spreads across 25,000 miles, from the southern tip of South America all the way to New Zealand. Roughly 90% of all earthquakes occur in the ring, with the majority of those quakes resulting from a small number of locations where plates are exceptionally active.
A. NO CHANGE
B. along with
C. in addition to
D. and
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2/17/26
At least in moderate amounts, stress may not be as harmful as we think. In fact, research suggests that people who view stress as a form of motivation perform better under pressure and have less health complaints than those who view stress as debilitating.
A. NO CHANGE
B. less health complaints then
C. fewer health complaints than
D. fewer health complaints then
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2/16/26
In a downtown park in the city of Kumamoto on Kyushu, the southwestern-most of Japan’s main islands, a group of locals can be found trying consistently to complete what could be called the world’s hardest jigsaw puzzle. It’s a problem so large that the pieces cover the size of a football field, a riddle so challenging that it will take them nearly 20 years to complete.
Which choice most strongly emphasizes that the group is focusing intently on the puzzle?
A. NO CHANGE
B. painstakingly
C. excitedly
D. impulsively
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2/15/26
Citrus trees are among the most widely cultivated fruit trees in the world, but until recently, their history has been unclear. Seeking to obtain a better understanding of where these trees originated, the genomes of more than 50 varieties of citrus fruit were analyzed by researchers in the United States and Spain, from the Chinese mandarin to the Seville orange.
A. NO CHANGE
B. an analysis of the genomes of more than 50 varieties of citrus fruit was performed in the United States and Spain by researchers,
C. more than 50 varieties of citrus fruit had their genomes analyzed by researchers in the United States and Spain,
D. researchers in the United States and Spain analyzed the genomes of more than 50 varieties of citrus fruit,
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2/14/26
Creativity is often defined as the ability to come up with new and useful ideas. Like intelligence, it can be considered a trait that everyone, not just creative geniuses possesses in some capacity.
A. NO CHANGE
B. geniuses that possess
C. geniuses possesses,
D. geniuses, possesses
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2/13/26
The origins of saffron are a mystery: competing claims place the wild plants beginning’s in regions along a wide swath of land, from Greece in the eastern Mediterranean all the way to Central Asia.
A. NO CHANGE
B. plants beginnings
C. plant’s beginnings
D. plant’s beginnings’
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2/12/26
At any given time, the vast majority of the volcanic activity on Earth isn’t occurring in continent-covering floods of magma or in explosions like the one at Mount St. Helens. Rather, it’s on the seafloor, where the tectonic plates are spreading apart. As the Earth’s crust splits, the mostly solid mantle layer raises to fill the space created.
A. NO CHANGE
B. raises for filling
C. rises to fill
D. rises in filling
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2/11/26
The fight between the Earth’s magnetic field and the solar wind produces some surprising effects, including: the Aurora, or the Northern and Southern Lights, which can appear when the highly charged particles from the sun hit the Earth’s atmosphere, causing a glowing green light display.\
A. NO CHANGE
B. effects, including the Aurora, or the Northern and Southern Lights,
C. effects, including the Aurora, or the Northern and Southern Lights;
D. effects including the Aurora or the Northern, and Southern Lights
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2/10/26
It is well known that seismic activity can affect hydrologic activity—that is, the movement of water. In the aftermath of nearby large earthquakes, dry streams can start flowing, well levels can go up or down, and eruptions of geysers sometimes occur.
Which choice best maintains the pattern already established in the sentence?
A. NO CHANGE
B. sometimes geysers will erupt.
C. geysers can sometimes erupt.
D. there is an eruption of geysers sometimes.
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2/9/26
Generally speaking, solar eruptions are caused by a sudden, violent rearrangement of the Sun’s magnetic field. At a deeper level, however, the process is controlled by two types of structures that form in the magnetic field of the Sun: ropes and cages. The rope is confined within the magnetic cage. If the cage is strong, it can contain the rope’s contortions, but when the cage is weak, an eruption can cause it to rip through.
As it is used in the last sentence, the word “contain” most nearly means
A. encompass
B. restrict
C. exclude
D. comprehend
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2/8/26
Scientists have found that animals across the spectrum have a keen sense of quantity, able to distinguish not just bigger from smaller or more from less, but two from four, four from ten, and forty from sixty. Orb-weaving spiders, for instance, keep a tally of how many silk-wrapped prey items are stashed in the “larder” segment of their web. In one experiment, scientists removed the items. Despite this, the spiders spent time searching for the stolen goods in direct proportion to how many separate items had been taken.
A. NO CHANGE
B. Subsequently,
C. However,
D. Likewise,
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2/7/26
Whatever the truth behind the origins of macaroni and cheese, this humble dish has become an ultimate comfort food in many cultures and countries, each with their own favored variations.
A. NO CHANGE
B. they’re
C. its
D. its’
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2/6/26
All frozen water consists of molecules arranged in a hexagonal structure similar to a honeycomb; however, the ice coating bobsled tracks or the firm, flattened snow of a ski course is precisely shaped and conditioned, optimizing the properties of this frosty form of water.
A. NO CHANGE
B. firm, flattened, snow of a ski course
C. firm flattened snow, of a ski course
D. firm, flattened snow of a ski course,
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2/5/26
The appearance of tiny cracks in concrete can be harmful because they provide an easy route of entry in for liquids and gasses – and the harmful substances they contain. Even a slender breach the width of a hair can let enough water in to undermine the concrete’s integrity. For example, micro-cracks can allow water and oxygen to infiltrate and then corrode steel supports, causing a structure to collapse.
If the author were to delete the underlined portion, the paragraph would primarily lose
A. a detail that emphasizes the dangerous consequences of tiny imperfections in concrete.
B. a claim that shifts the paragraph away from the discussion of harmful substances.
C. a comment that introduces the main idea of the paragraph.
D. irrelevant information that distracts from the focus of the paragraph.
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2/4/26
Maglev—or magnetic levitation—trains, which use magnets to lift a train above its rails, reducing friction, and increasing possible speeds are already in operation. The most famous one takes passengers from downtown Shanghai to the city’s airport at 270 miles per hour. But of the plans to make a maglev even faster by putting it in a vacuum tube, Hyperloop One is the most advanced.
A. NO CHANGE
B. reducing friction, and to increase possible speeds,
C. reducing friction and increasing possible speeds,
D. reduce friction, and increasing possible speeds
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2/3/26
A new type of vaccine, which could become available in the United States over the next few years, is made by growing viruses in cultures of animal cells rather than with chicken eggs.
A. NO CHANGE
B. in
C. to
D. from
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2/2/26
A factory needs robots to perform repetitive tasks at high volume 24 hours a day. The most common robots are large industrial machines dedicated to specific processes that run independently and can be more than six feet tall and 30 feet long.
A. NO CHANGE
B. processes, which run independently and can be
C. processes. These machines run independently and can be
D. processes; running independently and being
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2/1/26
Sleep-inducing substances may come from the process of making new connections between neurons. Sleep researcher, Chiara Cirelli, suggests that since making these connections, or synapses, is what our brains do when we are awake, maybe what they do during sleep is scale back the unimportant ones, removing the memories or images that don’t fit with the others, or don’t need to be used to make sense of the world.
A. NO CHANGE
B. researcher, Chiara Cirelli
C. researcher Chiara Cirelli,
D. researcher Chiara Cirelli
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