【正文】 or the presence of dead fish along the edges of ponds and streams during the Devonian.B. To support the claim that climate change caused freshwater habitats to bee more restricted during the Devonian.C. To identify a consequence of the emergence of plants into terrestrial habitats near ponds and streams.D. To identify a possible reason for why certain fish gradually became terrestrial organisms.10. According to paragraph 4，teeth of the earliest tetrapods suggest that these tetrapodsA. peted with other animals for proteinB. were probably carnivoresC. could easily climb out of waterD. were able to eat plants11. According to paragraph 5, which of the following was true of the first tetrapods?A. They became dependent for food on organisms already living on land.B. They needed to develop new mechanisms for obtaining nutrients.C. They continued to live in close association with aquatic environments.D. They were evolutionarily far removed from their rhipidistian ancestors.12. According to paragraph 5, what was the main way that the earliest tetrapods differed from their immediate fish ancestors?A. The tetrapods had a different skeletal structure.B. The tetrapods had more sources of food availableC. The tetrapods had a circulation system.D. The tetrapods could move to new pools of water.13. Look at the four squares [■] that indicate where the following sentence could be added to the passage.These would have been deposited by the receding waters of droughts, during which many aquatic animals must have died.Where would the sentence best fit? Click on a square [■] to add the sentence to the passage14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.Drag your answer choices to the spaces where they belong. To remove an answer choice, click on it.To review the passage, click VIEW TEXTFreshwater lobefinned fish may be the direct ancestors of terrestrial tetrapods.A. Rhipidistian crossopterygian had features such as primitive lungs and thick fins that could have helped it survive dry periods.B. During the Devonian, the number of bones increased in the fins of rtiipidistians, improving such animals’ ability to swim and move over landC. Shortly after the earliest tetrapods developed lungs, plants and other animals began to flourish on land.D. By the Devonian period, lobefinned fish preferred freshwater habitats to life in the ocean.E. A drier climate and new sources of food on land may have encouraged the lobefinned fish’smove to a terrestrial existence.F. Early tetrapods remained closely connected to water, but several of their body structures were adapted for life on land.托福TPO44閱讀文本+題目+答案下載上海新航道整理！更多托福TPO閱讀查看，請移步：更多托福TPO查看，請點擊： 托福TPO寫作大全 托福TPO口語大全 托福TPO聽力大全1. From Fish to Terrestrial VertebratesOne of the most significant evolutionary events that occurred on Earth was the transition of waterdwelling fish to terrestrial tetrapods (fourlimbed organisms with backbones). Fish probably originated in the oceans, and our first records of them are in marine rocks. However, by the Devonian Period (408 million to 362 million years ago), they had radiated into almost all available aquatic habitats, including freshwater settings. One of the groups whose fossils are especially mon in rocks deposited in fresh water is the lobefinned fish.The freshwater Devonian lobefinned fish rhipidistian crossopterygian is of particular interest to biologists studying tetrapod evolution. These fish lived in river channels and lakes on large deltas. The delta rocks in which these fossils are found are monly red due to oxidized iron minerals, indicating that the deltas formed in a climate that had alternate wet and dry periods. If there were periods of drought, any adaptations allowing the fish to survive the dry conditions would have been advantageous. In these rhipidistians，several such adaptations existed. It is known that they had lungs as well as gills for breathing. Cross sections cut through some of the fossils reveal that the mud filling the interior of the carcass differed in consistency and texture depending on its location inside the fish. These differences suggest a sadlike cavity below the front end of the gut that can only be interpreted as a lung. Gills were undoubtedly the main source of oxygen for these fish, but the lungs served as an auxiliary breathing device for gulping air when the water became oxygen depleted, such as during extended periods of drought. So, these fish had already evolved one of the prime requisites for living on land: the ability to use air as a source of oxygen.A second adaptation of these fish was in the structure of the lobe fins. The fins were thick, fleshy, and quite sturdy, with a median axis of bone down the center. They could have been used as feeble lootor devices on land, perhaps good enough to allow a fish to flop its way from one pool of water that was almost dry to an adjacent pond that had enough water and oxygen for survival. These fins eventually changed into short, stubby legs. The bones of the fins of a Devonian rhipidistian exactly match in number and position the limb bones of the earliest known tetrapods, the amphibians. It should be emphasized that the evolution of lungs and limbs was in no sense an anticipation of future life on land. These adaptations developed because they helped fish to survive in their existing aquatic environment.What ecological pressures might have caused fishes to gradually abandon their watery habitat and bee increasingly landdwelling creatures? Changes in climate during the Devonian may have had something to do with this i