GRE Admission Tests GRE General Test Free Practice Exam Questions (2025 Updated)

As originally formulated, the selfish-herd theory of prey species aggregation assumed that predatory attacks were equally likely to be launched from any position within the environment. In some circumstances (e.g.. avian predators attacking prey from above), such an approach is appropriate. However, as James et al. argue, in many predator-prey associations, attacks are unlikely to occur from positions within the group. For example, it is likely that an ambushing predator waiting in the path of a group would be detected before the group moves over its position. Hence, in many ecological situations, predatory attacks on grouped prey will occur exclusively from outside the group. In such circumstances, there is a strong premium to a group member in being in the interior of the group.

James would most likely describe the original formulation of the selfish-herd theory as

Recent research has questioned the long-standing view of pearly mussels as exclusively suspension feeders (animals that strain suspended particles from water) that subsist on phytoplankton (mostly algae). Early studies of mussel feeding were based on analyses of gut contents, a method that has three weaknesses. First, material in mucus-bound gut contents is difficult to identify and quantify. Second, material found in the gut may pass undigested out of the mussel, not contributing to its nutrition. Finally, examination of gut contents offers limited insight into the mechanisms and behaviors by which mussels acquire food. Modem studies suggest that pearly mussels feed on more than just algae and may use other means than suspension feeding. Pedal feeding (sweeping up edible material with a muscular structure called the foot) has been observed in juvenile pearly mussels.

Besides the phytoplankton pearly mussels capture from the water column, their guts also contain small animals, protozoans, and detritus (nonliving particulate organic material). Recent studies show that mussels can capture and assimilate bacteria as well, a potentially important source of food in many fresh waters. Another potential source of food for mussels is dissolved organic matter. Early studies showing that pearly mussels could take up simple organic compounds were largely discounted because such labile (unstable) compounds are rarely abundant in nature. Nevertheless, recent work on other bivalves suggests that dissolved organic matter may be a significant source of nutrition.

Of this complex mix of materials that pearly mussels acquire, what is actually required and assimilated? Stable-isotope analyses of mussels taken from nature and of captive-reared mussels are beginning to offer some insight into this question. Nichols and Garling showed that pearly mussels in a small river were omnivorous, subsisting mainly on particles less than 2S micrometers in diameter, including algae, detritus, and bacteria. Bacterially derived carbon was apparently the primary source of soft-tissue carbon. However, bacteria alone cannot support mussel growth, because they lack the necessary long-chain fatty acids and sterols and are deficient in some amino acids. Bacteria may supplement other food resources, provide growth factors, or be the primary food In habitats such as headwater streams, where phytoplankton is scarce. Juvenile mussels have been most successfully reared m the laboratory on diets containing algae high in polyunsaturated fatty acids. Thus, it appears that the pearly mussel diet in nature may consist of algae, bacteria, detritus, and small animals and that at least some algae and bacteria may be required as a source of essential biochemicals.

Which of the following can be inferred about the "recent research?

Even if the merits of the proposal are (i)_________, faculty members may be reluctant to (ii)_________given their fear of offending the group that champions it.

Despite the (i)_________nature of contemporary science, the (ii)_________of many individuals (iii)_________: the work of women and minority scientists has too often been exploited or deemed rudimentary and unworthy of inclusion into science history books.

Scholars generally estimate subscribers to Freedom s Journal (1827-1829), the United States" first African American newspaper, at around 800. based on subscriptions to the Rights of AIL an African American newspaper founded in 1829 as a successor to Freedom s Journal by a former editor of that newspaper. But Gross argues that many more than 800 readers probably subscribed to Freedom s Journal because many of its subscribers, dissatisfied with the direction ultimately taken by the paper, refused to subscribe to the Rights of All. In any case, the figure of 800 subscribers would make the circulation of Freedom s Journal close to that of other weekly papers of the time Its number of readers, however, would have been much larger: copies were often shared. and African American organizations subscribed to Freedom s Journal, providing nonsubscribers access to the paper

African American organizations' subscriptions to Freedom s Journal are mentioned in the passage primarily in order to.

Adapting to its changing environment and building its own ecological niche in interactions with other disciplines, the scientific discipline of ecology can be seen as highly_________.

Instances of "galactic cannibalism"—mergers in which large galaxies completely consume smaller ones—may be fairly common. Tidal forces produced by the Milky Way's powerful gravity, for example, appear to be dismantling and engulfing a dwarf galaxy in the constellation Sagittarius, producing large clumps and streamers of stars connecting the two galaxies. Astronomers have also observed two dense clusters of stars and gas at the heart of the Andromeda galaxy, an apparent "double nucleus" that may contain the remnant of a cannibalized dwarf galaxy. But this twin-lobed appearance could also be created by two parts of a single nucleus bisected by a lane of dust. Scientists believe that only about 25 percent of such apparent double nuclei actually represent galactic cannibalism. Many of the rest result from the illusion of proximity that occurs when objects at different distances appear along the same line of sight: others consist of debris from galactic "collisions." in which one galaxy has passed through another without merging, causing waves of new star formation.

The primary purpose of the passage is to

The iacl thai ihcre are so many varieties of youthful dissent indicates that there is considerably less_________to this counterculture than has been suggested.

Many environmentalists who revere nature would find the intellectual traditions of Rousseau. Kropotkin. and Jefterson much more compatible with their vision than that of Marx, who_________the domination of nature by humans.

Female Australian Dunalothrips [small, sap-sucking insects] create tent-like structures on the surface of leaves to protect themselves and their eggs and larvae from desiccation in the arid Australian climate. Bono and Crespi compared survival and reproduction of thrips that founded structures alone with those in groups of two or more individuals. They found that although per capita egg production fell with increasing group size, foundresses were more likely to survive and lay eggs in groups than when alone. Several studies of other species of nest-building insects have concluded that foundress associations are beneficial to all panics. It is likely that the relative success of groups is at least in part accounted for by a reduction of energy use in the modification of a shared nest.

The author suggests which of the following about the "reduction of energy use"?

The inventory of confirmed planets outside our solar system is growing rapidly, although it is_________by the fact that it is easier to detect big planets than small ones and planets close to their parent stars than those farther away.

Because most of the fish and waterfowl observed in the Arctic Ocean are (i)_________species, disruptive changes at all levels of the Arctic food chain that have resulted from rapid warning and loss of sea ice there will (ii)_________ ecosystems in more southerly habitats.

Harriet Monroe, who founded Poetry: A Magazine of Verse in 1912. argued that the more heterogeneous and sprawling the modem world became, the more poetry needed "an entrenched place, a voice of power." Hut this goal could only be realized if poets were valued in ways that encouraged them to participate in the world and made writing verse economically viable. Monroe argued that poets needed sites of institutional opportunity like those that had been developed for visual artists, architects, and musicians. She believed that the hand-wringing anticapitalism dominating genteel literary culture—particularly the idea that poetry ought to be removed from "sordid" pecuniary considerations—brought no economic and only illusory aesthetic benefits, instead severing poets from meaningful participation in the modern world.

The passage suggests that Monroe believed that finding "an entrenched place, a voice of power" for poetry would rely on which of the following?

In 1995 the United States National Park Service reintroduced wolves into Yellowstone National Park, from which they had been eliminated decades before by overhunting. Biologists hoped the reintroduction would return the park's mix of animals to a more natural state. After the wolves* disappearance, the population of their onetime prey, the elk. had burgeoned. Subsequently, new tree growth declined as multiplying elk browsed young trees, denuding certain areas of the park. Following the wolves" return, the elk population declined and young trees rebounded. Most scientists attribute the vegetation changes to the wolves" return. However. Patton observes that Yellowstone has not had a harsh winter since wolf numbers reached high levels and suggests that elk may not have needed to resort to trees for food.

If the view attributed to the majority of scientists is correct, which of the following must be true?

In contrast to today, when many readers consider the moral sentiments expressed in the ancient writer’s work to be quite sophomoric. in the writer'! own tune these sentiments were regarded as remarkably________.

There is a long-standing historical presumption that social custom during the early years of the United States forbade women from public speaking. In fact, though, the standard mode of education of the 1790s and early 1800s. which emphasized oral recitation and performance, taught girls that educated and well-spoken women had an important role to play in American society. By depicting skilled speech as a necessary talent for women in a civilized society, elocutionary education encouraged a certain degree of female ambition and even political involvement. Transmitted via standard, inexpensive schoolbooks. this message reached virtually all who read schoolbooks or attended schools. This environment did not last long, however: even by the 1S10s. attitudes about women's education had changed considerably.

The author would probably agree with which of the following statements about the "historical presumption"?

She constantly_________herself for not living up to her own ideals—for not working hard enough, or not having motives that were pure enough.

People who come to believe false rumors often do so quite (i)_________in the sense mat their new belief

(ii)_________their existing knowledge. This problem is especially acute on the Internet. Rumors often arise and gain

traction because they fit with, and support, the prior convictions of those who accept them.

Cole makes the argument that while some advocates of government transparency seem to treat any exposure of state secrets as an (i)_________. that position is (ii)_________; there are many legitimate bases for (hi)_________ disclosures. Cole contends, particularly when they reveal the identities of sources and methods of foreign intelligence.