TOEFL IBT Reading Practice Test 27 from Cambridge Preparation for the TOEFL Test Four Edition by Jolene Gear – Robert Gear
Reading Section Directions
The Reading section measures your ability to read and understand passages in English. You will read three passages and answer questions about them. Answer all questions based on what is stated or implied in the passages.
Most questions are worth one point. The last question in each set is worth more than one point. For this question, the directions will indicate how many points you can receive.
Some passages have one or more words in bold type. For these bolded words, you will see a definition in a glossary at the end of the passage.
Allow 20 minutes to read each passage and answer the questions about it. You may now begin the first passage.
Questions 1-12
Panspermia
The idea that life did not originate on Earth, but was carried here either deliberately or by natural processes, has its roots at least as far back as the ancient Greeks. This idea, often referred to as panspermia, took on a scientific form in the work of various nineteenth-century authors. It later gained widespread popular appeal through the work of the Swedish chemist Svante Arrhenius, who argued that spores of life could survive in space and travel between star systems through the pressure of solar radiation.
The panspermia hypothesis eventually fell out of favor for a variety of reasons. Skeptics pointed out that microorganisms could not possibly survive the damage caused by ultraviolet radiation and cosmic rays while being propelled out of a solar system away from a star. Indeed, it was unclear how biological material could escape from a planet by natural processes in the first place. If unprotected, the molecules of life would quickly be destroyed by radiation near the ejecting planet. Furthermore, it was not clear how microorganisms, having made a journey across the huge distances of interstellar space, could have safely descended to the surface of the Earth or any other planet. Arrhenius himself argued that organisms caught inside meteorites would be subjected to incandescent* temperatures while entering the atmosphere of a terrestrial body. Such heat would destroy any life-forms lucky enough to have survived to this point.
Despite the seeming implausibility* of the panspermia hypothesis, some theorists have resurrected the notion in recent decades since laboratory research has shown that many of the objections to the hypothesis can be overcome. Scientists have shown that microorganisms protected from radiation by grains of material could be ejected from a solar system if the repulsive force (p) of the ejecting star is greater than the attractive force (g) of the star’s gravity. Such ejecting stars cannot be too luminous since brighter stars emit too much ultraviolet radiation for the survival of bacteria. Organisms can only enter new solar systems whose stars’ p/g ratio is low, thus allowing the gravity to pull the microbes into the planetary orbits. According to some researchers, material ejected from a planetary system could also eventually become part of an interstellar molecular cloud, which eventually produces a new planetary system as well as a large number of comets. Comets can retain microorganisms protected by other material and water, and impact onto new planets, which j by then would have cooled sufficiently for the life in the grains to take hold.
Further supporting evidence about the likelihood of survival of bacteria traveling through space and entering a planetary atmosphere has been gained from studies of a meteorite of Martian origin found in Antarctica in 1984. Whether or not the meteorite contains fossils of Martian bacteria (and many researchers now seem to reject this possibility), microscopic studies of its internal structure have shown that the interior was not heated to more than 40 degrees Celsius since before leaving the Martian surface. In other words, neither the original impact that must have ejected the rock away from the Martian surface nor the heat generated by its entry into the Earth’s atmosphere did, in fact, melt or vaporize the internal portions of the meteorite. So it is quite possible that any life-form that had undergone such a trip would survive. As for the long journey itself, experiments aboard a European Space Agency mission have shown that bacterial spores can survive in deep space for at least five years. This is sufficient time for viable interplanetary travel, although not, of course, for interstellar travel.
Today, the panspermia hypothesis is being regarded with less skepticism than formerly. Although the orthodox view is still that life evolved on Earth (and possibly other planets in the universe) without extraterrestrial input, more and more research is pointing to the feasibility of some form of interstellar “seeding.” Wickramasinghe and Hoyle, who championed the hypothesis of the interstellar transmission of life during the 1970s, argued persuasively that prebiotic chemicals have been shown to exist by remote sensing data of Comet Hailey. Furthermore, they point out that evidence for viable microorganisms existing in comets could be attained in the near future if unmanned space missions could capture and return to Earth with cometary material.
‘incandescent: producing a bright light after being heated to a high temperature
*implausibility: the condition of being difficult to believe
| 1. Early supporters of the panspermia hypothesis A. rejected the main elements of the hypothesisB. argued that some primitive life has been detected on a cometC. pointed out that space missions will find life elsewhereD. suggested that the “seeds” of life may have been deliberately planted |
[Refer to the full passage.] |
2. The word “propelled” in the passage is closest in meaning to
A. rejected
B. plunged
C. heaved
D. thrust
The panspermia hypothesis eventually fell out of favor for a variety of reasons. Skeptics pointed out that microorganisms could not possibly survive the damage caused by ultraviolet radiation and cosmic rays while being propelled out of a solar system away from a star. Indeed, it was unclear how biological material could escape from a planet by natural processes in the first place. If unprotected, the molecules of life would quickly be destroyed by radiation near the ejecting planet. Furthermore, it was not clear how microorganisms, having made a journey across the huge distances of interstellar space, could have safely descended to the surface of the Earth or any other planet. Arrhenius himself argued that organisms caught inside meteorites would be subjected to incandescent temperatures while entering the atmosphere of a terrestrial body. Such heat would destroy any life-forms lucky enough to have survived to this point.
3. According to the passage, the panspermia hypothesis fell out of favor for all of the following reasons EXCEPT
A. the potential damage caused by ultraviolet radiation
B. the unlikelihood of natural processes leading to the ejection of biological material
C. the probability that heat would destroy incoming life-forms
D. the knowledge that life can’t exist elsewhere in the universe
[Refer to the full passage.]
4. The word “resurrected” in the passage is closest in meaning to
A. destroyed
B. reintroduced
C. initiated
D. succeeded
Despite the seeming implausibility of the panspermia hypothesis, some theorists have resurrected the notion in recent decades since laboratory research has shown that many of the objections to the hypothesis can be overcome. Scientists have shown that microorganisms protected from radiation by grains of material could be ejected from a solar system if the repulsive force (p) of the ejecting star is greater than the attractive force (g) of the star’s gravity. Such ejecting stars cannot be too luminous since brighter stars emit too much ultraviolet radiation for the survival of bacteria. Organisms can only enter new solar systems whose stars’ p/g ratio is low, thus allowing the gravity to pull the microbes into the planetary orbits. According to some researchers, material ejected from a planetary system could also eventually become part of an interstellar molecular cloud, which eventually produces a new planetary system as well as a large number of comets. Comets can retain microorganisms protected by other material and water, and impact onto new planets, which by then would have cooled sufficiently for the life in the grains to take hold.
5. The word “retain” in the passage is closest in meaning to
A. prevent
B. erode
C. avert
D. keep
Despite the seeming implausibility of the panspermia hypothesis, some theorists have resurrected the notion in recent decades since laboratory research has shown that many of the objections to the hypothesis can be overcome. Scientists have shown that microorganisms protected from radiation by grains of material could be ejected from a solar system if the repulsive force (p) of the ejecting star is greater than the attractive force (g) of the star’s gravity. Such ejecting stars cannot be too luminous since brighter stars emit too much ultraviolet radiation for the survival of bacteria. Organisms can only enter new solar systems whose stars’ p/g ratio is low, thus allowing the gravity to pull the microbes into the planetary orbits. According to some researchers, material ejected from a planetary system could also eventually become part of an interstellar molecular cloud, which eventually produces a new planetary system as well as a large number of comets. Comets can retain microorganisms protected by other material and water, and impact onto new planets, which by then would have cooled sufficiently for the life in the grains to take hold.
6. According to the passage, the panspermia hypothesis is
A. of historical interest only
B. being taken seriously again
C. not really good science
D. probably true
[Refer to the full passage.]
7. The word “its” in the passage refers to
A. the Martian
B. the bacteria
C. the meteorite
D. the interior
Further supporting evidence about the likelihood of survival of bacteria traveling through space and entering a planetary atmosphere has been gained from studies of a meteorite of Martian origin found in Antarctica in 1984. Whether or not the meteorite contains fossils of Martian bacteria (and many researchers now seem to reject this possibility), microscopic studies of its internal structure have shown that the interior was not heated to more than 40 degrees Celsius since before leaving the Martian surface. In other words, neither the original impact that must have ejected the rock away from the Martian surface nor the heat generated by its entry into the Earth’s atmosphere did, in fact, melt or vaporize the internal portions of the meteorite. So it is quite possible that any life-form that had undergone such a trip would survive. As for the long journey itself, experiments aboard a European Space Agency mission have shown that bacterial spores can survive in deep space for at least five years. This is sufficient time for viable interplanetary travel, although not, of course, for interstellar travel.
8. The phrase “such a trip” in the passage refers to
A. a journey from Mars to Earth
B. te descent through Earth’s atmosphere
C. a trip from another solar system C
D. interstellar traveling
Further supporting evidence about the likelihood of survival of bacteria traveling through space and entering a planetary atmosphere has been gained from studies of a meteorite of Martian origin found in Antarctica in 1984. Whether or not the meteorite contains fossils of Martian bacteria (and many researchers now seem to reject this possibility), microscopic studies of its internal structure have shown that the interior was not heated to more than 40 degrees Celsius since before leaving the Martian surface. In other words, neither the original impact that must have ejected the rock away from the Martian surface nor the heat generated by its entry into the Earth s atmosphere did, in fact, melt or vaporize the internal portions of the meteorite. So it is quite possible that any life-form that had undergone such a trip would survive. As for the long journey itself, experiments aboard a European Space Agency mission have shown that bacterial spores can survive in deep space for at least five years. This is sufficient time for viable interplanetary travel, although not, of course, for interstellar travel.
9. According to the passage, the meteorite found in Antarctica
A. does not contain bacteria fossils
B. might contain bacteria fossils
C. has fossils originating on Earth
D. could not originate from Mars
[Refer to the full passage.]
10. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.
A. Nowadays, the panspermia hypothesis has been more or less rejected.
B. Currently, the panspermia hypothesis is looked on with more astonishment than previously.
C. These days, the panspermia hypothesis is judged more plausible than before.
D. The modem scientific establishment now generally accepts the validity of the panspermia hypothesis.
Today, the panspermia hypothesis is being regarded with less skepticism than formerly. Although the orthodox view is still that life evolved on Earth (and possibly other planets in the universe) without extraterrestrial input, more and more research is pointing to the feasibility of some form of interstellar ‘seeding.” Wickramasinghe and Hoyle, who championed the hypothesis of the interstellar transmission of life during the 1970s, argued persuasively that prebiotic chemicals have been shown to exist by remote sensing data of Comet Hailey. Furthermore, they point out that evidence for viable microorganisms existing in comets could be attained in the near future if unmanned space missions could capture and return to Earth with cometary material.
11. Look at the four squares [■] that indicate where the following sentence could be added to the passage.
However, even if organisms were somehow shielded inside fine grains of carbon they would be too heavy to be ejected from a planetary system by the pressure of radiation.
Where would the sentence best fit?
Choose the letter of the square that shows where the sentence should be added.
The panspermia hypothesis eventually fell out of favor for a variety of reasons. [■A] Skeptics pointed out that microorganisms could not possibly survive the damage caused by ultraviolet radiation and cosmic rays while being propelled out of a solar system away from a star. Indeed, It was unclear how biological material could escape from a planet by natural processes in the first place. [■B] If unprotected, the molecules of life would quickly be destroyed by radiation near the ejecting planet. [■C] Furthermore, it was not clear how microorganisms, having made a journey across the huge distances of interstellar space, could have safely descended to the surface of the Earth or any other planet. [■D] Arrhenius himself argued that organisms caught inside meteorites would be subjected to incandescent’ temperatures while entering the atmosphere of a terrestrial body. Such heat would destroy any life-forms lucky enough to have survived to this point.
12. Directions: Select the appropriate phrases from the answer choices and match them to the category to which they relate. THREE of the answer choices will NOT be used This question is worth 4 points.
Write the letters of the answer choices in the spaces where they belong.
Refer to the full
| Answer Choices
A. Prebiotic chemicals exist in comets. B. Bright stars emit a lot of ultraviolet radiation. C. Distances in interstellar space are huge. D. Comets are made up of water and other materials. E. Interstellar space has ultraviolet radiation and cosmic rays. F. Meteorites are subjected to burning temperatures when entering Earth’s atmosphere. G. Meteorites from Mars have been found on Earth in areas of Antarctica where the cold temperatures protected life-forms. H. The meteorite found in Antarctica contained frozen fossils. I. Bacterial spores have been shown capable of surviving for several years in space. J. Stars with a repulsive force greater than their attractive force are able to eject material. |
Arguments Against Panspermia
Hypothesis * * * Support for Panspermia Hypothesis * * * * |