The professor casts doubt on the view that dinosaurs were endotherms in the reading passage.
First, the professor thinks that polar dinosaurs can not prove that dinosaurs were endotherms. From the reading passage, endotherms can survive in cool place, so dinosaurs living in polar were endotherms.0 k& @4 A) |8 x9 F9 a
这里的内容是听力的 应该标明。Polar area was warmer than now(today). It was warm enough for dinosaurs to live. But the professor says that dinosaurs could not migrate to polar. 这点听错了 应该是天如果冷了 恐龙可以冬眠或者迁移
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Second, in the reading passage, it says that dinosaurs had legs underneath their bodies so dinosaurs can be considered as endotherms. In the listening materials, the professor indicates that the view about legs can not make a decision about whether dinosaurs were endotherms. Dinosaurs grew可以这样搭配吗 large size. Dinosaurs had legs underneath their bodies because they need legs underneath to support their weights.
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Third, dinosaurs do had Haversian canals but this phenomenon can not play a role for proving that dinosaurs were endotherms. Actually, dinosaurs had growth string(ring), which dinosaurs would stop growing or growing slowly in cooler circumstance. And the growth string is a evidence to show dinosaurs were not endotherms. Human have no growth string so people can grow rapidly although in cool season.