Reading Section
Directions: These sample questions in the Reading section measureyour ability to understand academic passages in English. You will read onepassage and answer questions about it. In a real test, you would have 20minutes to read the passage and answer the questions. Candidates withdisabilities may request a time extension.
Meteorite Impact and Dinosaur Extinction
Thereis increasing evidence that the impacts of meteorites have had importanteffects on Earth, particularly in the field of biological evolution. Suchimpacts continue to pose a natural hazard to life on Earth. Twice in thetwentieth century, large meteorite objects are known to have collided withEarth.
If animpact is large enough, it can disturb the environment of the entire Earth andcause an ecological catastrophe. The best-documented such impact took place 65million years ago at the end of the Cretaceous period of geological history.This break in Earth’s history is marked by a mass extinction, when as many ashalf the species on the planet became extinct. While there are a dozen or moremass extinctions in the geological record, the Cretaceous mass extinction hasalways intrigued paleontologists because it marks the end of the age of thedinosaurs. For tens of millions of years, those great creatures had flourished.Then, suddenly, they disappeared.
Thebody that impacted Earth at the end of the Cretaceous period was a meteoritewith a mass of more than a trillion tons and a diameter of at least 10kilometers. Scientists first identified this impact in 1980 from the worldwidelayer of sediment deposited from the dust cloud that enveloped the planet afterthe impact. This sediment layer is enriched in the rare metal iridium and otherelements that are relatively abundant in a meteorite but very rare in the crustof Earth. Even diluted by the terrestrial material excavated from the crater,this component of meteorites is easily identified. By 1990 geologists hadlocated the impact site itself in the Yucatán region of Mexico. Thecrater, now deeply buried in sediment, was originally about 200 kilometers indiameter.
Thisimpact released an enormous amount of energy, excavating a crater about twiceas large as the lunar crater Tycho. The explosion lifted about 100 trilliontons of dust into the atmosphere, as can be determined by measuring thethickness of the sediment layer formed when this dust settled to the surface.Such a quantity of material would have blocked the sunlight completely fromreaching the surface, plunging Earth into a period of cold and darkness thatlasted at least several months. The explosion is also calculated to haveproduced vast quantities of nitric acid and melted rock that sprayed out overmuch of Earth, starting widespread fires that must have consumed mostterrestrial forests and grassland. Presumably, those environmental disasterscould have been responsible for the mass extinction, including the death of thedinosaurs.
Severalother mass extinctions in the geological record have been tentativelyidentified with large impacts, but none is so dramatic as the Cretaceous event.But even without such specific documentation, it is clear that impacts of thissize do occur and that their results can be catastrophic. What is a catastrophefor one group of living things, however, may create opportunities for anothergroup. Following each mass extinction, there is a sudden evolutionary burst asnew species develop to fill the ecological niches opened by the event.
Impactsby meteorites represent one mechanism that could cause global catastrophes andseriously influence the evolution of life all over the planet. According tosome estimates, the majority of all extinctions of species may be due to suchimpacts. Such a perspective fundamentally changes our view of biologicalevolution. The standard criterion for the survival of a species is its successin competing with other species and adapting to slowly changing environments.Yet an equally important criterion is the ability of a species to survive randomglobal ecological catastrophes due to impacts.
Earthis a target in a cosmic shooting gallery, subject to random violent events thatwere unsuspected a few decades ago. In 1991 the United States Congress askedNASA to investigate the hazard posed today by large impacts on Earth. The groupconducting the study concluded from a detailed analysis that impacts frommeteorites can indeed be hazardous. Although there is always some risk that alarge impact could occur, careful study shows that this risk is quite small.
1. The word “pose” on line 2 is closest in meaningto
a. claim
b. model
c. assume
d. present
2. In paragraph 2, why does the author includethe information that
dinosaurs had flourished for tens ofmillions of years and then suddenly
disappeared?
a. To support the claim that the mass extinctionat the end of the
Cretaceous is the best-documented of thedozen or so mass
extinctionsin the geological record
b. To explain why as many as half of the species on Earth at the time
arebelieved to have become extinct at the end of the Cretaceous
c. To explain why paleontologists have always been intrigued by the
mass extinction at the end of the Cretaceous
d. To provide evidence that an impact can be large enough to disturb
the environment of the entireplanet and cause an ecological
disaster
3. Which of the following can be inferred fromparagraph 3 about the
locationof the meteorite impact in Mexico?
a. The location of the impact site in Mexico was kept secret by
geologists from 1980 to 1990.
b. It was a well-known fact that the impact had occurred in the
Yucatán region.
c. Geologists knew that there had been an impact before they knew
where it had occurred.
d. The Yucatán region was chosen by geologists as the most probable
impactsite because of its climate.
4. According to paragraph 3, how did scientistsdetermine that a large
meteorite had impacted Earth?
a. They discovered a large crater in the Yucatán region of Mexico.
b. They found a unique layer of sedimentworldwide.
c. They were alerted by archaeologists who hadbeen excavating in
theYucatán region.
d. They located a meteorite with a mass of over a trillion tons.
5. The word “excavating” on line 25 is closestin meaning to
a. digging out
b. extending
c. destroying
d. covering up
6. The word “consumed” on line 32 is closest inmeaning to
a. changed
b. exposed
c. destroyed
d. covered
7. According to paragraph 4, all of thefollowing statements are true of
theimpact at the end of the Cretaceous period EXCEPT:
a. A large amount of dust blocked sunlight from Earth.
b. Earth became cold and dark for several months.
c. New elements were formed in Earth’s crust.
d. Large quantities of nitric acid were produced.
8. The phrase “tentatively identified” on line 36is closest in
meaningto
a. identified after careful study
b. identified without certainty
c. occasionally identified
d. easily identified
9. The word “perspective” on line 46 is closestin meaning to
a. sense of values
b. point of view
c. calculation
d. complication
10. Paragraph 6 supports which of the followingstatements about the
factors that are essential for the survival ofa species?
a. The most important factor for the survival of a species is its
ability to compete and adapt togradual changes in its
environment.
b. The ability of a species to compete and adapt to a gradually
changing environment is not theonly ability that is essential for
survival.
c. Since most extinctions of species are due to major meteorite
impacts, the ability to survive such impactsis the most
important factor for the survival of aspecies.
d. The factors that are most important for the survival of a species
vary significantly from one species toanother.
11. Which of the sentences below best expressesthe essential information in the
following sentence?
Earth is a target in a cosmic shootinggallery, subject to random violent
events that were unsuspected a few decadesago.
Incorrect choices change the meaning inimportant ways or leave out essential
information.
a. Until recently, nobody realized that Earth is exposed to
unpredictable violent impactsfrom space.
b. In the last few decades, the risk of a random violent impact from
space has increased.
c. Since most violent events on Earth occur randomly, nobody can
predict when or where they will happen.
d. A few decades ago, Earth became the target of random violent
events originating in outer space.
12. According to the passage, who conductedinvestigations about the
current dangers posed by large meteoriteimpacts on Earth?
a. Paleontologists
b. Geologists
c. The United States Congress
d. NASA
13. Look at the four letters (A, B,C, and D) that indicate where the
following sentence could be added to thepassage in paragraph 6.
Thisis the criterion emphasized by Darwin’stheory of
evolution by natural selection.
Where would the sentence best fit?
Impacts by meteorites represent one mechanismthat could cause
global catastrophes and seriously influencethe evolution of life all
over the planet. (A) According to some estimates, the majority of all
extinctions of species may be due to suchimpacts. (B) Such a
perspective fundamentally changes our view ofbiological evolution.
(C)The standard criterion for the survival of a species is its success
incompeting with other species and adapting to slowly changing
environments. (D) Yet an equally important criterion is the ability of
a species to survive random globalecological catastrophes due to
impacts.
Choose the place where the sentence fitsbest.
a. Option A
b. Option B
c. Option C
d. Option D
14. An introductory sentence for a brief summaryof the passage is
provided below. Complete the summary byselecting the THREE
answer choices that express the mostimportant ideas in the passage.
Some sentences do not belong in thesummary because they express
ideas that are not presented in thepassage or are minor ideas in the
passage. This question is worth 2 points.
Write your answer choices in the spaces where they belong. You can
write in the number of the answer choiceor the whole sentence.
Scientists have linked the mass extinction at the end of the Cretaceous with a meteorite impact on Earth.
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Answer choices
(1) Scientists had believed for centuries that meteorite activity influenced
evolution on Earth.
(2) The site of the large meteorite impact at the end of the Cretaceous
period was identified in 1990.
(3) There have also been large meteorite impacts on the surface of the
Moon, leaving craters like Tycho.
(4) An iridium-enriched sediment layer and a largeimpact crater in the
Yucatánprovide evidence that a large meteorite struck Earth about
65 million years ago.
(5) Large meteorite impacts, such as one at theend of the Cretaceous
period, can seriously affectclimate, ecological niches, plants, and
animals.
(6) Meteorite impacts can be advantageous for some species, which
thrive, and disastrous for other species,which become extinct.
Keyto Reading Section:
1. d
2. c
3. c
4. b
5. a
6. c
7. c
8. b
9. b
10. b
11. a
12. d
13. d
14.4,5,6