望过路牛牛好心指教~翻了考古贴，只有一道讨论过的

jyw0411lsq

OG10-53,心里的疑惑望牛牛们指教
Twodecadesafterthe 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 thedam 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 afterthe dam was built
has been 43 degrees.
(D)Nonnative species of fish, introduced into the Emerald River
afterthe 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.
感觉这道题目里面前半部分说温差变化从50到6，后面却说明温度升高能暗示繁殖，
这里面感觉有些偷换概念啊？？温差是个差量，而温度升高是温度点的变化， 能不能说明A为什么对啊，真的是想不明白~谢谢大家帮忙！

sdcar2010

A also talks about the RANGE!

ran2010zx

这道题是说关于range变化变小了
因此A说的再range跟以前一样的地方
reproduction还是一样
楼主要注意把题目看清楚哦

sdcar2010

Premise:
A dam is built.
None of the fish reproduce in the river below the dam.
The dam reduces the temperature range from 50 degrees to 6 degrees below the dam.

Conclusion:
Sharp rising temperatures signals the fish to reproduce.

Sharp rising temperatures = bigger range of temperature changes.

A supports the conclusion because it says where there is a bigger range in temperature, there is fish reproduction.

sally9031

妈呀~讲的真好！！！