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下面为大家整理的是一篇关于Weddell seal 的SAT文章阅读模拟题，后面附有相关题目。SAT文章阅读考试涉及到的类别很多，需要大家很多的练习。 Studies of the Weddell seal in the laboratory have described the physiological mechanisms that allow the seal to cope with the extreme oxygen deprivation that occurs during its longest dives, which can extend 500 meters below the oceans surface and last for over 70 minutes. Recent field studies, however, suggest that during more typical dives in the wild, this seals physio-logical behavior is different. In the laboratory, when the seal dives below the surface of the water and stops breathing, its heart beats more slowly, requiring less oxygen, and its arteries become constricted, ensuring that the seals blood remains concentrated near those organs most crucial to its ability to navigate underwater. The seal essentially shuts off the flow of blood to other organs, which either stop functioning until the seal surfaces or switch to an anaerobic metabolism. The latter results in the production of large amounts of lactic acid which can adversely affect the pH of the seals bloodbut since the anaerobic metabolism occurs only in those tissues which have been isolated from the seals blood supply, the lactic acid is released into the seals blood only after the seal surfaces, when the lungs, liver, and other organs quickly clear the acid from theseals blood-stream. | 
