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Unformatted text preview: e climates during the Late Cretaceous period
○An extreme decrease in the average yearly temperature over 10, ooo years
Paragraph 3: If true, though, why did coldblooded animals such as snakes, lizards, turtles, and crocodiles survive the freezing winters and torrid summers? These animals are at the mercy of the climate to maintain a livable body temperature. It’s hard to understand why they would not be affected, whereas dinosaurs were left too crippled to cope, especially if, as some scientists believe, dinosaurs were warmblooded. Critics also point out that the shallow seaways had retreated from and advanced on the continents numerous times during the Mesozoic, so why did the dinosaurs survive the climatic changes associated with the earlier fluctuations but not with this one? Although initially appealing, the hypothesis of a simple climatic change related to sea levels is insufficient to explain all the data.
3. Why does the author mention the survival of “snakes, lizards, turtles, and crocodiles” in paragraph 3? ○To argue that dinosaurs may have become extinct because they were not coldblooded animals
○To question the adequacy of the hypothesis that climatic change related to sea levels caused the extinction of the dinosaurs ○To present examples of animals that could maintain a livable body temperature more easily than dinosaurs
○To support a hypothesis that these animals were not as sensitive to climate changes in the Cretaceous period 251
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as they are today
4. The word cope in the passage is closest in meaning to ○adapt
5. According to paragraph 3, which of the following is true of changes in climate before the Cretaceous period and the effect of these changes on dinosaurs? ○Climate changes associated with the movement of seaways before the Cretaceous period did not cause dinosaurs to become extinct. ○Changes in climate before the Cretaceous period caused severe fluctuations in sea level, resulting in the extinction of the dinosaurs. ○Frequent changes in climate before the Cretaceous period made dinosaurs better able to maintain a livable body temperature. ○Before the Cretaceous period there were few changes in climate, and dinosaurs flourished.
6. The word fluctuations in the passage is closest in meaning to ○extremes
Paragraph 4: Dissatisfaction with conventional explanations for dinosaur extinctions led to a surprising observation that, in turn, has suggested a new hypothesis. Many plants and animals disappear abruptly from the fossil record as one moves from layers of rock documenting the end of the Cretaceous up into rocks representing the beginning of the Cenozoic (the era after the Mesozoic). Between the last layer of Cretaceous rock and the first layer of Cenozoic rock, there is often a thin layer of clay. Scientists felt that they could get an idea of how long the extinctions took by determining how long it took to deposit this one centimeter of clay and they thought they could determine the time...
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- Fall '13