Global warming looks like it will be a bigger problem for the world’s fish species than scientists first thought; A new study sh

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问题     Global warming looks like it will be a bigger problem for the world’s fish species than scientists first thought; A new study shows that when fish are laying eggs, they are more vulnerable to hotter water. With medium-level human-caused climate change expected by the end of the century, the world’s oceans, rivers and lakes will be too hot for about 40% of the world’s fish species in the egglaying stage, according to a study. That means they could go extinct or be forced to change how and where they live and reproduce.
    Until now, biologists had just studied adult fish. For adult fish, around 2% to 3% of the species would be in the too-hot zone in the year 2100 with similar projected warming. So using this new approach reveals a previously unknown problem for the future of fish, scientists said. In a worst case climate change scenario the figure for species in trouble jumps to 60%. These vulnerable times in the life of a fish make this a "bottleneck" in the future health of species, said Hans-Otto Portner, a marine biologist at the Alfred Wegener Institute in Germany.
    A marine heatwave last year caused large numbers of migrating salmon fish to die throughout Alaska’s rivers. It also killed off cod fish eggs, showing what a warmer future might be like, said Flemming Dahlke, a marine biologist at the institute. "With those fishes most sensitive to warming waters, it means fish populations won’t be able to replace themselves," said Rutgers University ecologist Malin Pinsky. "Without reproduction and offspring, we have no fish, no fishing and no fish on our plates. "
    In studying 694 species, Dahlke and Portner found some of the fish likely to be hardest hit by this phenomenon include Alaska pollock—the biggest fishery in the United States and the source of fast food fish slices—and well-known fish species such as sockeye salmon, brown trout, bonito, barracuda and swordfish. "The more we allow temperature to change, the more we will lose the natural foundation of human life, including food from the sea," Portner said. When it gets too warm for living, the species could still possibly move to someplace cooler or lay at another time, but that’s not easy, Dahlke said. "This could mean a lot of problems to many species.
Which of the following would be the best title for the text?

选项 A、How Do Fish Live in a Warmer World
B、Fish Are More Vulnerable to Warming Water than First Thought
C、Fish Have to Change Living Space
D、How Does Climate Change Influence the Earth

答案B

解析 主旨题。本文第一段对全文进行了主旨介绍,即鱼类在产卵时更容易受到高温水的影响,第二段对研究的内容做了介绍,第三段和第四段介绍了鱼类受到影响后可能会带来的后果。综合来看,全文的主旨还是以第一段所阐述的内容为主,故B项正确。原文并没有介绍鱼类如何在更高温度的世界生活,因此A项错误。C项是鱼类受到影响后的后果,不够宏观概括,排除。D项与主题无关,本文并没有提及气候变化对地球的影响,因此也排除。
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