GRE-TEST Online Practice Questions and Answers
Scientists have long debated the exact timing of the lunar cataclysm, a period approximately 4 billion years ago when Earth and the Moon were pummeled with asteroids. A clue to this puzzle may come from spherules, millimeter-sized droplets of molten rock formed after an asteroid collides explosively with a planet. Upon impact, the asteroid vaporizes both itself and the target rock. producing a vapor plume that condenses into spherules. These form a layer preserved in rock, whose age can be estimated using radiometric dating. Scientists know of fourteen of these spherule layers scattered across Earth, but none dates to the theorized lunar cataclysm time period. Four layers, however, are from between
3.47 and 3.24 billion years ago. indicating perhaps a slow decline in collisions.
Which of the following might plausibly account for the findings in the highlighted sentence?
A. Spherule layers older than 3.47 billion years exist, but they have not been discovered yet.
B. Spherule layers older than 3.47 billion years once existed, but they have since been destroyed.
C. Fewer asteroids collided with Earth than with the Moon during the lunar cataclysm.
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.
The primary purpose of the passage is to
A. summarize the present state of knowledge about what pearly mussels eat
B. contrast two mechanisms by which pearly mussels have been shown lo feed
C. explain why evidence used to support a long-standing view about pearly mussels is flawed
D. suggest that a particular source of nutrients is more essential to pearly mussels than was previously thought
E. question whether research findings about laboratory-reared pearly mussels can be extrapolated to pearly mussels in natural habitats
The poet Paul Laurence Dunbar (1872-1906) was the premier Black writer of poetry that used the dialect of rural African Americans of the southern United States. Although Dunbar's works were both popular with readers and acclaimed by literary critics during his lifetime, after the First World War a radical shift occurred, at least in critical opinion of his poetry, and twentieth-century critical evaluation of his work has been generally negative. Some critics attacked his work on social grounds for failing to challenge plantation stereotypes of African Americans. Other critics, such as the poet James Weldon Johnson, argued from aesthetic grounds that dialect poetry in general was too limited as an artistic medium, and capable of producing only two effects: pathos and humor. The negative critical trend only began to reverse itself in the 1970s, when scholars began to emphasize the importance of mythic, psychological, and historical dimensions of Dunbar's works, focusing on the interior and exterior realities of African American life after the Civil War.
Which of the following can be inferred from the passage concerning scholars' use of mythic, psychological, and historical considerations in evaluating Dunbar's works?
A. Such use disputes the claim that Dunbar's work failed to challenge plantation stereotypes of African Americans.
B. Such use challenges the claim that dialect poetry is well suited to producing effects of pathos and humor.
C. Such use supports the claim that Dunbar's poetry was aesthetically more limited when written in dialect.
D. Such use suggests that the initial reception accorded Dunbar's poetry may have been too positive.
E. Such use suggests that earlier twentieth-century evaluations of Dunbar's poetry may have been too negative.
The highly dispersed nature of Panzaleo pottery throughout present-day Ecuador has led archaeologists to speculate about the pottery's origins and significance. Jijon y Caamano attributed the pottery's distribution to trade, and based on the large quantities of pottery recovered in the Ambato-Latacunga region of the central Ecuadorian highlands, he proposed that region as the probable locus of production. However. Porras suggests that inhabitants of the subtropical eastern Andean slopes, or montafta, were the original producers of Panzaleo. Porras: theory involves the forced migration of the montaria population from their homeland in the Quijos River valley into the Ecuadorian highlands. The gradual exodus and ensuing dispersal of the makers of this ware could account for the diffuse distribution of the materials.
The passage cites evidence supporting which of the following hypotheses?
A. Jijon y Caamaflos hypothesis about the relationship between trade and the distribution of Panzaleo pottery
B. Jijon y Caamanos hypothesis about the probable locus of Panzaleo pottery production
C. Porrasr hypothesis about who the original producers of Panzaleo pottery were
D. Porras' hypothesis about the forced migration of certain peoples
E. Porras' hypothesis about the dispersal of the original makers of Panzaleo porter)"
Scholars generally estimate subscribers to Freedom z 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 X 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
Which of the following, if true, would most lend to undermine Gross's argument mentioned in the highlighted portion of the passage?
A. A larger number of African American organizations subscribed to Freedom s Journal than to The Rights of Ail.
B. While many of the subscribers to Freedom s Journal did become dissatisfied with the paper over time, most of its readers were initially highly supportive of the paper
C. Many people who had not subscribed to Freedom s Journal bought subscriptions to The Rights of All.
D. The editorial direction of The Rights of All followed closely the direction that Freedom s Journal had taken.
E. Copies of The Rights of Alt were shared more frequently with nonsubscribers than were copies of Freedom s Journal.
The story lines of silent dramas may often have been_________. yet within those basic narrative outlines,
the true artists among silent-film actors could express emotional shadings that have no analogue in spoken
A. language.
B. implausible
C. incredible
D. conventional
E. elemental
F. rudimentary
G. confusing
A. Quantity A is greater.
B. Quantity B is greater.
C. The two quantities are equal.
D. The relationship cannot lie determined from the information given.
If the sum of two positive prime numbers is 5. which of the following is a multiple of the product of the two numbers?
A. 46
B. 45
C. 44
D. 39
Pumping at a constant rate, a certain gasoline pump can fill an empty 50-gallon tank in 2 minutes. If the pump pumped gasoline into the 50-gallon tank at the constant rate for 1.5 minutes and the tank had 10 gallons of gasoline in it when the pump began pumping, what percent of the volume of the 50-gallon tank was filled with gasoline at the end of the 1.5 minutes?
A. % 95s