GMAT考满分·题库

搜索

收录题目9362道

搜索结果共9178条

来源 题目内容
Anole lizard species that occur together (sympatrically) on certain Caribbean islandsoccupy different habitats: some live only in the grass, some only on tree trunks, and some only on twigs. These species also differ morpho-logically: grass dwellers are slender with long tails, tree dwellers are stocky with long legs, twig dwellers are slender but stubby-legged. [hl:1]What is striking about these lizards is not that coexisting species differ in morphology and habitat use (such differences are common among closely related sympatric species), but that the same three types of habitat specialists occur on each of four islands: Puerto Rico, Cuba, Hispaniola, and Jamaica.[/hl:1] Moreover, the Puerto Rican twig species closely resembles the twig species of Cuba, Hispaniola, and Jamaica in morphology, habitat use, and behavior. Likewise, the spe- cialists for other habitats are similar across the islands.The presence of similar species on different islands could be variously explained. An ancestral species might have adapted to exploit a particular ecological niche on one island and then traveled over water to colonize other islands. Or this ancestral species might have evolved at a time when the islands were connected, which some of these islands may once have been. After the islands separated, the isolated lizard populations would have become distinct species while also retaining their ancestors' niche adaptations. Both of these scenarios imply that specialization to each niche occurred only once. Alternatively, each specialist could have arisen independently on each of the islands.If each type of specialist evolved just once, then similar specialists on different islands would be closely related. Conversely, if the specialists evolved independently on each island, then a specialist on one island would be more closely related to other types of anoles on the same island-regardless of their ecological niches- than it would be to a similar specialist on a different island.Biologists can infer how species are related evolutionarily by comparing DNA sequences for the same genes in different species. Species with similar DNA sequences for these genes are generally more closely related to each other than to species with less-similar DNA sequences. DNA evidence concerning the anoles led researchers to conclude that habitat specialists on one island are not closely related to the same habitat specialists elsewhere, indicating that specialists evolved independently on each island.
A key decision required of advertising managers is whether a "hard-sell" or "soft-sell" strategy is appropriate for a specific target market. The hard-sell approach involves the use of direct, forceful claims regarding the benefits of the advertised brand over competitors` offerings. In contrast, the soft-sell approach involves the use of advertising claims that imply superiority more subtly.One positive aspect of the hard-sell approach is its use of very simple and straightforward product claims presented as explicit conclusions, with little room for confusion regarding the advertiser`s message. However, some consumers may resent being told what to believe and some may distrust the message. Resentment and distrust often lead to counterargumentation and to boomerang effects where consumers come to believe conclusions diametrically opposed to conclusions endorsed in advertising claims. By contrast, the risk of boomerang effects is greatly reduced with soft-sell approaches. One way to implement the soft-sell approach is to provide information that implies the main conclusions the advertiser wants the consumer to draw, but leave the conclusions themselves unstated. [line:25][hl:7]Because consumers are invited to make up their own minds, implicit conclusions reduce the risk of resentment, distrust, and counterargumentation. [/hl:7][/line:25]Recent [line:29][hl:3][hl:8]research[/hl:8][/hl:3][/line:29] on consumer memory and judgment suggests another advantage of implicit conclusions. Beliefs or conclusions that are self generated are more accessible from memory than beliefs from conclusions provided explicitly by other individuals, and thus have a greater impact on judgment and decision making. Moreover, self-generated beliefs are often perceived as more accurate and valid than the beliefs of others, because other individuals may be perceived as less knowledgeable, or may be perceived as manipulative or deliberately misleading.Despite these advantages, implicit conclusions may not always be more effective than explicit conclusions. One risk is that some consumers may fail to draw their own conclusions and thus miss the point of the message. Inferential activity is likely only when consumers are motivated and able to engage in effortful cognitive processes. Another risk is that some consumers may draw conclusions other than the one intended. Even if inferential activity is likely there is no guarantee that consumers will follow the path provided by the advertiser. Finally, a third risk is that consumers may infer the intended conclusion but question the validity of their inference.
The single-celled parasite known as Toxoplasma gondii infects more than half of the world's human population without creating any noticeable symptoms. Once inside the human body, Toxoplasma rapidly spreads to the heart and other organs. It can even penetrate the tight barrier that normally protects the brain from most pathogens. Yet, the blood of infected persons carries very few free-floating Toxoplasma cells. Scientists have long been puzzled by this ability of Toxoplasma to parasitize the human body without triggering an immune response and without an appreciable presence in the bloodstream. Recent research, however, has shed light on the ways in which Toxoplasma achieves its remarkable infiltration of the human body.Though there are few individual Toxoplasma cells coursing freely in the blood of an infected person, scientists have discovered that the parasite is quite common in certain cells, known as dendritic cells, involved in the human immune system. Dendritic cells are found in the digestive tract and frequently come into contact with the various pathogens that enter the human body through food and water. When the dendritic cells encounter pathogens, they travel to lymph nodes and relay this information to other immune cells that then take action against the reported pathogen. Scientists have found, however, that Toxoplasma is capable of hijacking dendritic cells, forcing them from their usual activity and using them as a form of transportation to infect the human body quickly. Without this transport mechanism, Toxoplasma could not reach the better-protected areas of the body.Toxoplasma invades the human body through consumption of the undercooked meat of infected animals, primarily pigs and chickens. Other animals, such as cats, can become infected as well. In fact, cats are a necessary component in the reproductive cycle of Toxoplasma, since the animal's intestines are the parasite's sole breeding ground. Toxoplasma creates egg-like cysts, known as oocysts, in the cats' intestines. These oocysts are shed in the cats' droppings and contaminate ground water and soil, eventually finding their way into the food chain. Because Toxoplasma must somehow find its way into a new host cat in order to reproduce, it cannot kill its current host. Instead, it waits for the host, usually a small rodent, to be eaten by a cat, thus providing Toxoplasma the opportunity to reproduce.
C13

     In semi-aquatic ecosystems, bodies of water present peculiar difficulties for the hunting strategies of spiders. Ponds, lakes, and rivers can provide unnavigable escape vectors for prey organisms, making it likely that predators will lose out on valuable nutritional resources. The water spider Dolomedes, in particular, demonstrates adaptations that allow it to take advantage of waterborne food sources.

     The difficulty that members of the species Dolomedes face is best evidenced by the typical hunting strategies of terrestrial spiders. All spiders produce silk and arboreal species generally spin their silk into fine, latticework structures that they suspend in the environment to trap passing arthropods, which entangle themselves due to the exigencies of the forested ecosystem. In environs lacking tree coverage or comparable large structures, however, web-hunting becomes inefficient, and other strategies of predation have to be pursued. That many spider species persist in environments lacking significant tree coverage suggests that certain behavioral adaptations enable them to locate food effectively in a variety of environmental circumstances.

     One such adaptation is the proactive use of water bodies by Dolomedes, who eschew silk in favor of water tension, which they use to monitor the movements of prey animals. Organisms fall into a pond, lake, or river, and send waves vibrating from the point of impact across the surface of the pool. Dolomedes uses these vibrations to locate and capture the fallen organism. For arboreal spiders, who can only monitor the vibrations caused by insects caught in the webs they've spun, this is useless information. Such a hunting strategy does not require that the arboreal spiders pay attention to extraneous prey when other prey is acquired in abundance by other adaptations. In comparison, Dolomedes acquires its prey by yet another aquatic adaptation, using a coat of tiny, hydrophobic hairs that allow the spider to submerge itself in the liquid environment. By causing a pocket of air to gather and surround the surface of the spider's body, these hairs allow Dolomedes to submerge itself in water, thus giving it access to sources of prey closed off to other species.
A key decision required of advertising managers is whether a "hard-sell" or "soft-sell" strategy is appropriate for a specific target market. The hardsell approach involves the use of direct, forceful claims regarding the benefits of the advertised brand over competitors' offerings. In contrast, the soft-sell approach involves the use of advertising claims that imply superiority more subtly. One positive aspect of the hard-sell approach is its use of very simple and straightforward product claims presented as explicit conclusions, with little room for confusion regarding the advertiser's message. However, some consumers may resent being told what to believe and some may distrust the message. Resentment and distrust often lead to counterargumentation and to boomerang effects where consumers come to believe conclusions diametrically opposed to conclusions endorsed in advertising claims. By contrast, the risk of boomerang effects is greatly reduced with soft-sell approaches. One way to implement the soft-sell approach is to provide information that implies the main conclusions the advertiser wants the consumer to draw, but leave the conclusions themselves unstated. [line:25]Because consumers are invited to make up their own minds, implicit conclusions reduce the risk of resentment, distrust, and counterargumentation.[/line:25]
Recent [hl:7]research[/hl:7] on consumer memory and judgment suggests another advantage of implicit conclusions. Beliefs or conclusions that are selfgenerated are more accessible from memory than beliefs from conclusions provided explicitly by other individuals, and thus have a greater impact on judgment and decision making. Moreover, selfgenerated beliefs are often perceived ·as more accurate and valid than the beliefs of others, because other individuals may be perceived as less knowledgeable, or may be perceived as manipulative or deliberately misleading. Line Despite these advantages, implicit conclusions may not always be more effective than explicit conclusions. One risk is that some consumers may fail to draw their own conclusions and thus miss the point of the message. Inferential activity is likely only when consumers are motivated and able to engage in effortful cognitive processes. Another risk is that some consumers may draw conclusions other than the one intended. Even if inferential activity is likely there is no guarantee that consumers will follow the path provided by the advertiser. Finally, a third risk is that consumers may infer the intended conclusion but question the validity of their inference.
The traditional model of employer-employee relations in the United States was a "psychological contract" in which employees made long-term commitments to organizations in exchange for long-term job security, training and development, and internal opportunities for promotion. Beginning mainly with the recession in the early 1970's, this paradigm began to unravel. Organizations began using extensive downsizing and outsourcing to decrease the number of permanent employees in the workforce. Among employees this situation has resulted in a decided shift in desire: instead of working their way up in an organization, many now prefer to work their way out. Entrepreneurship at the small business administration are now the fastest-growing majors in business schools.Several factors have generated movement from the old paradigm to the new one. Organizations have had legitimate and pressing reasons to shift to a [hl:4]new paradigm[/hl:4] of employer-employee relations. Large numbers of permanent employees make it difficult for organizations to respond quickly to downturns in demand by decreasing payroll costs. The enormous rights in wrongful discharge suites has created incentives for organizations to use temporary, contract, and leased employees in order to distance themselves from potential litigation problems. Moreover, top management is under increased pressure from shareholders to generate higher and higher levels of return on investment in the short run, resulting in declines in hiring, increases in layoffs, and shortage of funds for employee development.At the same time, a lack of forthrightness on the part of organizations has led to increased cynicism among employees about management's motivation and competence. Employees are now working 15 percent more hours per week than they were 20 years ago, but organizations acknowledge this fact only by running stress-management workshops to help employees to cope. Sales people are being asked to increase sales at the same time organizations have cut travel, phone, and advertising budgets. Employees could probably cope effectively with changes in the psychological contract if organizations were more forthright about how they were changing it. But the euphemistic jargon used by executives to justify the changes they were implementing frequently backfires; rather than engendering sympathy for management's position, it sparks employees' desire to be free of the organization all together. In a recent study of employees' attitudes about management, 49 percent of the sample strongly agreed that "management will take advantage of you if given the chance."
Two modes of argumentation have been used onbehalf of women's emancipation in Western societies.Arguments in what could be called the "relational"feminist tradition maintain the doctrine of "equality indifference," or equity as distinct for equality. Theyposit that biological distinctions between the sexesresult in a necessary sexual division of labor in thefamily and throughout society and that women's procreative labor is currently undervalued by society, tothe disadvantage of women. By contrast, the individualist feminist tradition emphasizes individual human rightsand celebrates women's quest for personal autonomy,while downplaying the importance of gender roles andminimizing discussion of childbearing and its attendantresponsibilities.Before the late nineteenth century, these viewscoexisted within the feminist movement, often withinthe writings of the same individual. Between 1890 nd1920, however, relational feminism, which had been thedominant strain in feminist thought, and which still predominates among European and non-Western feminists,lost ground in England and the United States. Becausethe concept of individual rights was already well established in the Anglo-Saxon legal and political tradition,individualist feminism came to predominate in Englishspeaking countries. At the same time, the goals of thetwo approaches began to seem increasingly irreconcilable. Individualist feminists began to advocate a totallygender-blind system with equal rights for all. Relationalfeminists, while agreeing that equal educational andeconomic opportunities outside the home should be available for all women, continued to emphasize women'sspecial contributions to society as homemakers andmothers; they demanded special treatmentincluding protective legislation for women workers,state-sponsored maternity benefits, and paid compensation for housework.Relational arguments have a major pitfall: becausethey underline women's physiological and psychologicaldistinctiveness, they are often appropriated by politicaladversaries and used to endorse male privilege. But theindividualist approach, by attacking gender roles, denying the significance of physiological difference, andcondemning existing familial institutions as hopelesslypatriarchal, has often simply treated as irrelevant thefamily roles important to many women. If the individualist framework, with its claim for women's autonomy,could be harmonized with the family-oriented concernsof relational feminists, a more fruitful model for contemporary feminist politics could emerge.
Magoosh GMAT、gmat题库、gmat模考、gmat考满分The figure on the left is an isosceles right triangle, and the figure on the right is a square of length 3. What is the value of b?Statement #1: b is the length of the diagonal of the square.Statement #2: the triangle and the square have the same area.
Magoosh GMAT、gmat题库、gmat模考、gmat考满分In the diagram above, A is the center of the circle, angle BAD = 90°, and the area of triangle ABD is $$24\sqrt{3}$$. Point C is the intersection of segment BD with the circle. What is thearea of the circle? Statement #1: AB = 12Statement #2: AD = CD
Manhattan In the rectangular coordinate plane points X and Z lie on the same line through the origin and points W and Y lie on the same line through the origin. If$$ a^{2} + b^{2} = c^{2} + d^{2} and e^{2} + f^{2} = g^{2} + h^{2}$$, what is the value of length XZ – length WY?GMAT、gmat题库、gmat模考、gmat考满分
OG19-数学分册 Company X's profits this year increased by 25% over last year's profits. Was the dollar amount of Company X's profits this year greater than the dollar amount of Company Y's? (1) Last year, the ratio of Company Y's profits to Company X's profits was 5:2. (2) Company Y experienced a 40% drop in profits from last year to this year.
OG20 OG2022 A rectangular solid has length, width, and height of L cm, W cm, and H cm, respectively. If these dimensions are increased by x%, y%, and z%, respectively, what is the percentage increase in the total surface area of the solid? 1.L, W, and H are in the ratios of 5:3:4. 2.x = 5, y = 10, z = 20
A researcher discovered that people who have low levels of immune-system activity tend to score much lower on tests of mental health than do people with normal or high immune-system activity.The researcher concluded from this experiment that the immune system protects against mental illness as well as against physical disease.The researcher's conclusion depends on which of the following assumptions?
The operation $$\Theta$$ is defined by $${x}\Theta{y}=\frac{1}{x}+\frac{1}{y}$$ for all nonzero numbers x and y. If z is a number greater than 1, which of the following must be true? I. $$z\Theta(-z) = 0$$II.$${z}\Theta{\frac{z}{z-1}}={1}$$III. $$(\frac{2}{z})\Theta(\frac{2}{z})={z}$$
What is the charge per hour of the $${1}_{st}$$ year associate at a law firm?1. The $${3}_{rd}$$ year associate charges $300 per hour.2. The $${2}_{nd}$$ year associate charges $${1}\cdot\frac{1}{2}$$ times more than the $${1}_{st}$$ year associate, and the $${3}_{rd}$$ year associate charges two times more than the $${2}_{nd}$$ year.
PREP07 Test 2 Linda, Robert, and Pat packed a certain number of boxes with books. What is the ratio of the number of boxes of books that Robert packed to the number of boxes of books that Pat packed? (1) Linda packed 30 percent of the total number of boxes of books. (2) Robert packed 10 more boxes of books than Pat did.
PREP07 Test 1 For a certain set of n numbers, where n > 1, is the average (arithmetic mean) equal to the median?(1) If the n numbers in the set are listed in increasing order, then the difference between any pair of successive numbers in the set is 2.(2) The range of the n numbers in the set is 2(n - 1).
Manhattan Parent: The city education department is unable to distinguish between annoyances and important problems. For instance, prohibiting students from having cell phones is an overreaction. If a student uses one and thus interferes with instruction, confiscate it. All in all, we need educational leadership that can solve problems, not create them. Which of the following is an assumption made by the parent?
PREP07 Test 2 A certain jar contains only b black marbles, w white marbles, and r red marbles. If one marble is to be chosen at random from the jar, is the probability that the marble chosen will be red greater than the probability that the marble chosen will be white?(1) $${{r}\over{b+w}}>{{w}\over{b+r}}$$(2) b – w > r
300难题 Tami purchased several identically priced metal frames and several identically priced wooden frames for a total pretax price of $144. What was the total pretax price of the metal frames that Tami purchased? 1.The price of each metal frame was 60% greater than the price of each wooden frame. 2.Tami purchased twice as many wooden frames as metal frames.