FREE Reading Comprehension Practice Problems for CAT

Tips on how to approach CAT Reading Comprehension passages
  • Don’t get into the minor details of the passage; just focus on what each paragraph has to say
  • As you read, create a map of the passage; you must remember what thing is located where in the passage
  • Once you read the question, come back to the part of the passage that is likely to have the answer
  • Compare the options and eliminate the incorrect choices based on the evidence that you see in the passage
  • Choose the answer once you are convinced of the right choice

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Reading Comprehension Practice Passage

Milankovitch proposed in the early twentieth century that the ice ages were caused by variations in the Earth’s orbit around the Sun. For sometime this theory was considered untestable, largely because there was no sufficiently precise chronology of the ice ages with which the orbital variations could be matched.

To establish such a chronology it is necessary to determine the relative amounts of land ice that existed at various times in the Earth’s past. A recent discovery makes such a determination possible: relative land-ice volume for a given period can be deduced from the ratio of two oxygen isotopes, 16 and 18, found in ocean sediments. Almost all the oxygen in water is oxygen 16, but a few molecules out of every thousand incorporate the heavier isotope 18. When an ice age begins, the continental ice sheets grow, steadily reducing the amount of water evaporated from the ocean that will eventually return to it. Because heavier isotopes tend to be left behind when water evaporates from the ocean surfaces, the remaining ocean water becomes progressively enriched in oxygen 18. The degree of enrichment can be determined by analyzing ocean sediments of the period, because these sediments are composed of calcium carbonate ) shells of marine organisms, shells that were constructed with oxygen atoms drawn from the surrounding ocean. The higher the ratio of oxygen 18 to oxygen 16 in a sedimentary specimen, the more land ice there was when the sediment was laid down.

As an indicator of shifts in the Earth’s climate, the isotope record has two advantages. First, it is a global record: there is remarkably little variation in isotope ratios in sedimentary specimens taken from different continental locations. Second, it is a more continuous record than that taken from rocks on land. Because of these advantages, sedimentary evidence can be dated with sufficient accuracy by radiometric methods to establish a precise chronology of the ice ages. The dated isotope record shows that the fluctuations in global ice volume over the past several hundred thousand years have a pattern: an ice age occurs roughly once every 100,000 years. These data have established a strong connection between variations in the Earth’s orbit and the periodicity of the ice ages.

However, it is important to note that other factors, such as volcanic particulates or variations in the amount of sunlight received by the Earth, could potentially have affected the climate. The advantage of the Milankovitch theory is that it is testable: changes in the Earth’s orbit can be calculated and dated by applying Newton’s laws of gravity to progressively earlier configurations of the bodies in the solar system. Yet the lack of information about other possible factors affecting global climate does not make them unimportant.


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Question: In the passage, the author is primarily interested in

suggesting an alternative to an outdated research method
introducing a new research method that calls an accepted theory into question
emphasizing the instability of data gathered from the application of a new scientific method
presenting a theory and describing a new method to test that theory
initiating a debate about a widely accepted theory

Question: The author of the passage would be most likely to agree with which of the following statements about the Milankovitch theory?

It is the only possible explanation for the ice ages.
It is too limited to provide a plausible explanation for the ice ages, despite recent research findings.
It cannot be tested and confirmed until further research on volcanic activity is done.
It is one plausible explanation, though not the only one, for the ice ages.
It is not a plausible explanation for the ice ages, although it has opened up promising possibilities for future research.

Question: It can be inferred from the passage that the isotope record taken from ocean sediments would be less useful to researchers if which of the following were true?

It indicated that lighter isotopes of oxygen predominated at certain times.
It had far more gaps in its sequence than the record taken from rocks on land.
It indicated that climate shifts did not occur every 100,000 years.
It indicated that the ratios of oxygen 16 and oxygen 18 in ocean water were not consistent with those found in fresh water.
It stretched back for only a million years.

Question: According to the passage, which of the following is true of the ratios of oxygen isotopes in ocean sediments?

They indicate that sediments found during an ice age contain more calcium carbonate than sediments formed at other times.
They are less reliable than the evidence from rocks on land in determining the volume of land ice.
They can be used to deduce the relative volume of land ice that was present when the sediment was laid down.
They are more unpredictable during an ice age than in other climatic conditions.
They can be used to determine atmospheric conditions at various times in the past.

Question: It can be inferred from the passage that precipitation formed from evaporated ocean water has

the same isotopic ratio as ocean water
less oxygen 18 than does ocean water
less oxygen 18 than has the ice contained in continental ice sheets
a different isotopic composition than has precipitation formed from water on land
more oxygen 16 than has precipitation formed from fresh water

Question: According to the passage, which of the following is true of the ice ages?

I. The last ice age occurred about 25,000 years ago.
II. Ice ages have lasted about 10,000 years for at least the last several hundred thousand years.
III. Ice ages have occurred about every 100,000 years for at least the last several hundred thousand years.
I only
II only

Question: It can be inferred from the passage that calcium carbonate shells

are not as susceptible to deterioration as rocks
are less common in sediments formed during an ice age
are found only in areas that were once covered by land ice
contain radioactive material that can be used to determine a sediment’s isotopic composition
reflect the isotopic composition of the water at the time the shells were formed

Question: The purpose of the last paragraph of the passage is to

offer a note of caution
introduce new evidence
present two recent discoveries
summarize material in the preceding paragraphs
offer two explanations for a phenomenon

Question: According to the passage, one advantage of studying the isotope record of ocean sediments is that it

corresponds with the record of ice volume taken from rocks on land
shows little variation in isotope ratios when samples are taken from different continental locations
corresponds with predictions already made by climatologists and experts in other fields
confirms the record of ice volume initially established by analyzing variations in volcanic emissions
provides data that can be used to substantiate records concerning variations in the amount of sunlight received by the Earth

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