Two decades after the Emerald River Dam was built, none of the eight fish species native to the Emerald River was still reproducing adequately in the river below the dam. Since the dam reduced the annual range of water temperature in the river below the dam from 50 degrees to 6 degrees, scientists have hypothesized that sharply rising water temperatures must be involved in signaling the native species to begin the reproductive cycle.
Which of the following statements, if true, would most strengthen the scientists' hypothesis?
发现逻辑题其实难不是难在逻辑推理上,主要是难在阅读上。要是读懂了,多难的题目也不会错到哪去。如下这个OG的53题,我怎么也读不懂呀。我的理解如下: 说是大坝的修建造成8个种类的鱼都不在河里进行足够的繁殖,又说大坝导致水温升高。科学家假设水温导致了不断向鱼传达繁殖期到来的讯息。 没错吧?既然繁殖少了,怎么会由于水温升高导致向鱼传达繁殖期到来的讯息。我理解不通。请DX点拨! 53. Two decades after the Emerald River Dam was built, none of the eight fish species native to the Emerald River was still reproducing adequately in the river below the dam. Since the dam reduced the annual range of water temperature in the river below the dam from 50 degrees to 6 degrees, scientists have hypothesized that sharply rising water temperatures must be involved in signaling the native species to begin the reproductive cycle. Which of the following statements, if true, would most strengthen the scientists’ hypothesis? (A) The native fish species were still able to reproduce only in side streams of the river below the dam where the annual temperature range remains approximately 50 degrees. (B) Before the dam was built, the Emerald River annually overflowed its banks, creating backwaters that were critical breeding areas for the native species of fish. (C) The lowest recorded temperature of the Emerald River before the dam was built was 34 degrees, whereas the lowest recorded temperature of the river after the dam was built has been 43 degrees. (D)Nonnative species of fish, introduced into the Emerald River after the dam was built, have begun competing with the declining native fish species for food and space. (E) Five of the fish species native to the Emerald River are not native to any other river in North America.
以下是我的理解: 这道题目evidence是the dam reduced the annual range of water temperature in the river below the dam from 50 degrees to 6 degrees,conclusion是sharply rising water temperatures must be involved in signaling the native species to begin the reproductive cycle。要support对象是这个conclusion,即水温上升是本土鱼开始进入繁殖周期的信号。
答案A:The native fish species were still able to reproduce only in side streams of the river below the dam where the annual temperature range remains approximately 50 degrees.说明了本土鱼在大坝附近水温较高的地方可以繁殖(一定程度上排除了其他原因导致不能生存)支持了这个结论。
scientists have hypothesized that sharply rising water temperatures must be involved in signaling the native species to begin the reproductive cycle.Since the dam reduced the annual range of water temperature in the river below the dam from 50 degrees to 6 degrees。 Two decades after the Emerald River Dam was built, none of the eight fish species native to the Emerald River was still reproducing adequately in the river below the dam.
Pay attention to "RANGE of water temperature" and "SHARPLY rising". Big Range (before) => sharply rising => Reproduction Small Range (now) => no sharply rising => NO Reproduction