Nokea
Neurologists and biological psychologists have witnessed a sharp increase in the knowledge and understanding of particular structures of the brain over the past two decades. As technology becomes ever more advanced, scientists are able to isolate the functions of even small regions of the human brain.
One noteworthy discovery is the role of the amygdala in human fear and aggression. The amygdala, a small, almond-shaped conglomerate, is just one part of the limbic system. Located at the very center of the brain, the limbic system is the core of our 'emotional brain;' each individual structure in the limbic system is somehow connected to an aspect of human emotion. Scientists have found that electrode stimulation of the amygdala can elicit extreme and aggressive acts. Patients or experimental subjects who experience this utter rage and fearlessness have no rational foundation for their reaction. In other words, this aggression is wholly attributable to electrode stimulation.
On the other hand, patients with trauma or damage to this structure exhibit a complete absence of aggression. Researchers find that no amount of poking, prodding, or harassment will evoke even remotely aggressive responses from these subjects
The author suggests that persistent passivity and imperturbability may be a direct result of which of the following?
- A. Drug-induced stimulation of the amygdala.
- B. A stroke that resulted in severe tissue damage in the limbic system.
- C. Encephalitis as a result of head trauma.
- D. Activation of a strategically implanted electrode in a patient's amygdala.
Correct Answer: B
Rationale: The correct answer is B. The passage highlights that damage to the limbic system, specifically the amygdala, can lead to passivity and lack of aggression. This is supported by the statement that patients with trauma or damage to the amygdala exhibit a complete absence of aggression. Thus, a stroke causing severe tissue damage in the limbic system, including the amygdala, can result in persistent passivity and imperturbability. Choices A, C, and D are incorrect because they do not directly relate to damage in the limbic system, which is specifically mentioned in the passage as the cause of the described behaviors.
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Linking San Francisco to Marin County in California, the Golden Gate Bridge is one of the most famous bridges in the world. The bridge crosses over a narrow strait which connects the Pacific Ocean to San Francisco Bay. Prior to the bridge, people traveled by ferry boat across the strait. Although most people thought a bridge was necessary to expedite travel, some residents of the Bay area felt the risk of building the bridge was too great. Joseph Strauss believed that nothing was impossible, and dreams would never come to fruition if risks weren't taken. So, he decided to gather the best and brightest builders, architects, and workers to embark on the challenge of building a bridge across the Golden Gate Strait. With safety nets in place, the construction began in 1937. Building the anchorages first, the builders then moved on to the towers on each end, and then to the three-foot-thick cables to support the suspension bridge. Lastly, workers labored to complete the roadway which became the most dangerous and treacherous part of the entire task. The builders had to keep the bridge balanced, so it wouldn't fall into the bay. Today, over sixty-five years later, the bridge remains a lifeline for the people of the San Francisco Bay Area
Why did Strauss set up a net during the construction of the Golden Gate Bridge?
- A. For suspension
- B. For balance
- C. For aesthetics
- D. For safety
Correct Answer: D
Rationale: Strauss set up a net to ensure the safety of the workers in case of falls during the construction of the Golden Gate Bridge. Safety nets were essential to protect the workers from potential accidents or falls while working on the bridge. Choice A ('For suspension') is incorrect as safety nets were not used for suspension purposes but rather for worker safety. Choice B ('For balance') is incorrect as the balance of the bridge was maintained by other construction elements, not safety nets. Choice C ('For aesthetics') is incorrect as safety nets are not related to the visual appearance of the bridge but rather to the protection of the workers.
The ability to see at a distance, in good light, does not diminish as a result of aging to the extent that other visual acuities do. Myopia, or nearsightedness, is more common to younger eyes, while presbyopia, or farsightedness, more commonly afflicts people as they age. The word presbyopia comes from Greek presbys, "old man," and opia, "eye," and names a condition in which, because the lens of the eye hardens slightly and loses elasticity as a person ages, one cannot as easily focus sharply on nearby objects. This condition leads to the familiar habit of lifting up one's glasses and bringing an object or reading material close to the face so that the eyes can more easily focus on it. The function of the lens is to accommodate different focal points so that sensory data can be correctly directed to the retina for interpretation into images by the brain. Corrective lenses, particularly bifocals or progressive lenses, adjust for the focal point aberration. In essence, they do the work that the eye can no longer do for itself
The author of the passage would probably agree with which of the following statements relating corrective lenses and aging eyes?
- A. A carpenter uses wood glue to fix a broken cabinet.
- B. A student buys a new notebook for upcoming classes.
- C. A chef sharpens knives before starting to cook.
- D. An athlete stretches before a game to avoid a potential injury.
Correct Answer: D
Rationale: The correct analogy for the role of corrective lenses in helping aging eyes can be compared to an athlete stretching before a game. Just as stretching prepares an athlete's body to perform optimally and avoid injury during a game, corrective lenses help aging eyes adjust and focus properly due to the hardening and loss of elasticity in the eye lens. Choices A, B, and C do not align with the concept of preparing or adjusting to address a specific issue, unlike the use of corrective lenses for aging eyes.
A nanometer is a billionth of a meter. A DNA molecule is 2 nanometers in diameter. Protein molecules are about 10 nanometers in diameter. A human hair is 100,000 nanometers in diameter. But what is a nanometer and how does it relate to technology?
Nanotechnology is defined as the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, a scale at which unique properties of materials emerge that can be used to develop novel technologies and products. At the nanoscale, the physical, chemical, and biological properties of materials differ from the properties of matter either at smaller scales, such as atoms, or at larger scales that we use in everyday life such as millimeters or inches.
Nanotechnology involves imaging, measuring, modeling, and manipulating matter only a few nanometers in size. Gold nanoparticles are made of the same material as in jewelry. But when light interacts with particles of gold, different colors are reflected. The different colors can be used in simple medical tests to indicate infection or disease. Metals such as copper become extremely rigid at the nanoscale, rather than bendable as in copper wires seen in everyday use.
What is the major difference between matter at the nanoscale and matter at larger scales such as millimeters or inches?
- A. At the nanoscale, metals are rigid, and at larger scales, they are bendable.
- B. Matter has different and special characteristics at the nanoscale.
- C. At the nanoscale, matter has different properties than matter at the atomic level.
- D. There is no difference.
Correct Answer: B
Rationale: The correct answer is B. Matter at the nanoscale exhibits unique and special characteristics that distinguish it from matter at larger scales. This can include properties like increased surface area, different melting points, altered conductivity, and enhanced reactivity. Choice A is incorrect as metals at the nanoscale can be more rigid compared to their larger scale counterparts. Choice C is incorrect because matter at the nanoscale has properties that are distinct from both atomic and larger scales. Choice D is incorrect as there are significant differences in how matter behaves and interacts at the nanoscale compared to larger scales.
Today, bicycles are so common that it's hard to believe they haven't always been around. But two hundred years ago, bicycles didn't even exist, and the first bicycle, invented in Germany in 1818, was nothing like our bicycles today. It was made of wood and didn't even have pedals. Since then, however, numerous innovations and improvements in design have made the bicycle one of the most popular means of recreation and transportation around the world.
In 1839, Kirkpatrick Macmillan, a Scottish blacksmith, dramatically improved upon the original bicycle design. Macmillan's machine had tires with iron rims to keep them from getting worn down. He also used foot-operated cranks like pedals, so his bicycle could be ridden at a quick pace. It didn't look much like a modern bicycle, though, because its back wheel was substantially larger than its front wheel.
In 1861, the French Michaux brothers took bicycle design a step further by introducing a metal frame, making bicycles stronger and lighter. They also used rubber tires, which provided better traction and allowed for a more comfortable ride.
Finally, in 1874, the first truly modern bicycle appeared on the scene, complete with solid rubber tires, ball bearings, and even a chain drive, which enabled the rider to pedal at a higher speed with less effort. Today bicycles are built, used, and enjoyed all over the world.
Why did Macmillan add iron rims to the tires of his bicycle?
- A. Increase the weight of the bicycle.
- B. Enhance the durability of the tires.
- C. Reduce the bumpiness of the ride.
- D. Decrease the level of fatigue during the ride.
Correct Answer: B
Rationale: Macmillan added iron rims to his bicycle tires to enhance their durability and make them last longer. This innovation aimed to prevent the tires from getting worn down quickly. Adding weight to the bicycle (Choice A) was not the purpose of adding iron rims. While adding iron rims could potentially reduce the bumpiness of the ride (Choice C) by providing more stability, the main objective was to improve tire longevity. Similarly, reducing the level of fatigue during the ride (Choice D) was not the primary reason for adding iron rims.
The Moon has been worshipped by primitive peoples and has inspired humans to create everything from lunar calendars to love sonnets, but what do we really know about it? The most accepted theory about the origin of the Moon is that it was formed of the debris from a massive collision with the young Earth about 4.6 billion years ago. A huge body, perhaps the size of Mars, struck the Earth, throwing out an immense amount of debris that coalesced and cooled in orbit around the Earth.The development of Earth is inextricably linked to the Moon; the Moon's gravitational influence upon the Earth is the primary cause of ocean tides. In fact, the Moon has more than twice the effect upon the tides than does the Sun. The Moon makes one rotation and completes a revolution around the Earth every 27 days, 7 hours, and 43 minutes. This synchronous rotation is caused by an uneven distribution of mass in the Moon (essentially, it is heavier on one side than the other) and has allowed the Earth's gravity to keep one side of the Moon permanently facing Earth. It is an average distance from Earth of 384,403 km.The Moon has no atmosphere; without an atmosphere, the Moon has nothing to protect it from meteorite impacts, and thus the surface of the Moon is covered with impact craters, both large and small. The Moon also has no active tectonic or volcanic activity, so the erosive effects of atmospheric weathering, tectonic shifts, and volcanic upheavals that tend to erase and reform the Earth's surface features are not at work on the Moon. In fact, even tiny surface features such as the footprint left by an astronaut in the lunar soil are likely to last for millions of years, unless obliterated by a chance meteorite strike. The surface gravity of the Moon is about one-sixth that of the Earth's. Therefore, a man weighing 82 kilograms on Earth would only weigh 14 kilograms on the Moon.
Why does the author mention 'impact craters' in line 16?
- A. To explain the corrosive effects of atmospheric weathering
- B. To explain why the Moon has no plant life because of meteorites
- C. To show the result of the Moon not having an atmosphere
- D. To show the result of the Moon not having active tectonic or volcanic activity
Correct Answer: C
Rationale: The mention of impact craters in the text is to highlight the consequence of the Moon lacking an atmosphere. The absence of an atmosphere on the Moon leaves it vulnerable to meteorite impacts, resulting in the multitude of impact craters on its surface. Choice A is incorrect because the mention of impact craters is not related to atmospheric weathering but rather to the lack of an atmosphere. Choice B is incorrect as it misinterprets the reason for the absence of plant life on the Moon. Choice D is incorrect as the text explicitly states that the Moon lacks tectonic or volcanic activity, which is not the focus of the mention of impact craters.