文勇的新托福黄金&ccedil

1920

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Unformatted text preview: temperatures ○They are distantly related to leatherback turtles. ○They can swim farther than leatherback turtles. Paragraph 2: A warm­blooded turtle may seem to be a contradiction in terms. Nonetheless, an adult leatherback can maintain a body tem perature of between 25 and 26°C (77 ­ 79°F) in seawaterthat is only 8 °C (46.4° F). Accomplishing this feat requires adaptations both to generate heat in the turtle' s bodyand to keep it from escaping into the surrounding waters. Leatherbacks apparently do not generate internal heat the way we do, or the way birds do, as a by­product of cellular metabolism. A leatherback may be able to pick up some body heat by basking at the surface; its dark, almost black body color may help it to absorb solar radiation. However, most of its internal heat comes from the action of its muscles. 3. The word feat in the passage is closest in meaning to ○remarkable achievement ○common transformation ○daily activity ○complex solution 4. Paragraph 2 mentions all of the following as true about the body heat of adult leatherback turtles EXCEPT: ○Their muscles produce heat for maintaining body temperature. ○Their clark bodies help trap solar radiation. ○Their cellular metabolism produces heat as a by­product. ○Basking at the waters surface helps them obtain heat. Paragraph 3: Leatherbacks keep their body heat in three different ways. The first, and simplest, is size. The bigger the animal is, the lower as surface to­volum e ratio; for every ounce of body mass, there is proportionately less surface through which heat can escape. An adult leatherback is twice the size of the biggest cheloniid sea turtles and will therefore take longer to cool off. Maintaining a high body temperature through sheer bulk is called gigantotherrny. It works for elephants, for whales, and, perhaps, it worked for many of the larger dinosaurs. It apparently works, in a smaller way, for some other sea turtles. Large loggerhead and green turtles can maintain their body temperature at a degree or two above that of the surrounding water, and gigantothermy is probably the way they do a. Muscular activity helps, too, and an actively swimming green turtle may be T C (12.6° F) warmer than the waters it swims through. 5. The word bulk in the passage is closest in meaning to ○strength ○effort ○activity ○mass Paragraph 4: Gigantothermy, though, would not be enough to keep a leatherback warm in cold northern waters. It is not enough for whales, which supplement it with a thick layer of insulating blubber (fat). Paragraph 5: Leatherbacks do not have blubber, but they do have a reptilian equivalent: thick, oil­ saturated skin, with a layer of fibrous, fatty tissue just beneath a. Insulation protects the leatherback 411 Mail@liuwenyong.com 在在在在在在 www.liuwenyong.com 在在在在在在在在在在在在在在在,在在在在在在在在在在 everywhere but on its head and flippers. Because the flippers are com paratively thin and blade like, they are the one part of the leatherback that is likely to become chilled. There is not much that the turtle can do about this without compromising the aerodynamic shape of the...
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