Directions: These GMAT reading comprehension practice questions are based on the content of this passage. Read the passage carefully and choose the best answer to each of the questions on the basis of what is stated or implied in the passage.
The Megatherium is an extinct type of giant ground sloth that lived from two million to perhaps 4,400 years ago. While medium-sized sloths continue to live in arborous habitats in Central and South America, the ground-dwelling Megatherium lived in parts of North and South America. These animals were as big as elephants and had huge claws on their feet. Evidence suggests three theories that may have contributed to the giant sloth’s extinction, which occurred at about the same time as humans arrived on the continent.
The first theory pertaining to the extinction of the giant ground sloth connects its disappearance with the arrival of humans. The most plausible explanation for this simultaneous action is that humans hunted the giant ground sloth to its extinction. Early humans hunted animals for a variety of reasons, but food and clothing were among the most important. They could eat the animals that they killed and then fashion the skins into clothing. Humans may also have killed animals as perceived threats, even if they were not valuable as a source of food or clothing. Scientists using radiocarbon to date giant sloth fossils from Cuba and Hispaniola recently found that the last record of a giant ground sloth coincided with the arrival of humans about 4,400 years ago.
The evidence found in favor of the human hunting hypothesis contrasts with a second theory that climate change was the primary reason for the giant ground sloth’s extinction. Some scientists think that the giant ground sloth was not able to adapt to the climate changes that followed the last Ice Age, which ended about 10,000 years ago. At the onset of the Ice Age, the Earth’s temperature dropped, and ice sheets and glaciers expanded. These changes would have affected the giant ground sloth’s eating habits, and evidence has been found to prove that the last surviving giant ground sloths had drastically different eating habits than their immediate predecessors.
A third theory has looked at the possibility of a hyper disease leading to the giant ground sloth’s extinction. This theory maintains that the giant ground sloth was particularly vulnerable to disease because of its large body size and small population. One suggestion is that the domestic dogs that humans brought with them transmitted pathogens to the giant ground sloth population. Critics of this theory state that it cannot account for several major extinction events that occurred before humans and domestic dogs migrated together. In Australia, for example, domesticated dogs did not arrive until 35,000 years after humans lived on the continent and 30,000 years after the giant ground sloth was believed to be extinct there.
Question for RC Practice Questions - 2
Try yourself:It can be inferred from the passage that if radiocarbon dating determined the last giant sloth fossils from Cuba and Hispaniola did NOT coincide with the arrival of humans, then:
Explanation
The correct answer is (D). Paragraph 2 implies that the fossils are currently used to support the idea that human hunting led to the giant ground sloth extinction because radiocarbon dating shows that the fossils correspond with the arrival of humans. By reverse reasoning, or inferring, you can deduce that if the fossils did NOT coincide with the arrival of humans, then human hunting as a cause of giant sloth extinction would be a less viable theory.
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Question for RC Practice Questions - 2
Try yourself:The overall tone of this passage can best be described as:
Explanation
The correct answer is (B). The tone of a passage indicates the general attitude or view of the author. In this passage, the author primarily takes a neutral approach; the passage is not highly emotionally charged or opinionated. The author remains almost transparent, offering unbiased information and explaining research. (B) is correct as the author does not blatantly insert personal opinion or resort to humor.
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Question for RC Practice Questions - 2
Try yourself:According to passage, the best evidence supporting the human hunting hypothesis is that:
Explanation
The correct answer is (D). The passage states that the Cuba and Hispaniola fossils, which are the last giant ground sloth fossils, correspond with the arrival of humans. This evidence is used to support the idea that humans hunted the giant ground sloth to extinction.
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Question for RC Practice Questions - 2
Try yourself:Which of the following statements would best conclude the ideas presented in this passage?
Explanation
The correct answer is (C). Approach this question by considering the context and tone of the entire passage. A concluding statement should agree with the ideas presented in the passage, tie them together somehow, and not offer new information. Each of the theories does not yet completely explain the extinctions, but the author of the passage presents evidence to suggest that each of the theories has some validity.
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Question for RC Practice Questions - 2
Try yourself:The author of this passage is primarily concerned with:
Explanation
The correct answer is (E). This passage begins by offering general information about the giant ground sloth, and each of the following paragraphs focuses on explaining a theory pertaining to its extinction. The best answer choice, then, will summarize these key points. (E) does this most effectively.
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Question for RC Practice Questions - 2
Try yourself:Which of the following findings, if true, would add further evidence to support the hyper-disease theory of giant ground sloth extinction?
Explanation
The correct answer is (A). Notice that this answer choice provides evidence that would undermine the criticism that the hyper disease theory "cannot account for several major extinction events that occurred before humans and domestic dogs migrated together." If ground sloths became entirely extinct when humans and dogs first migrated together to the area, then the several major extinction events that critics cite would not have occurred.
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