[問題]OG11th-DiagnosticTest-Q25

[aerobert]

Tiger beetles are such fast runners that they can capture virtually any nonflying insect. However、when running toward an insect、a tiger beetle will intermittently stop and then、a moment later、resume its attack. Perhaps the beetles cannot maintain their pace and must pause for a moment's rest; but an alternative hypothesis is that while running、tiger beetles are unable to adequately process the resulting rapidly changing visual information and so quickly do blind and stop.

Which of the following、if discovered in the experiments using artificially moved prey insects、would support one of the two hypotheses and undermine the other?

(A)When a prey insect is moved directly toward a beetle that has been chasing it、the beetle immediately stops and runs away without its usual intermittent stopping.

(B)In pursuing a swerving insect、a beetle alters its course while running and its pauses become more frequent as the chase progresses.

(C)In pursuing a moving insect、a beetle usually responds immediately to changes in the insect's direction、and it pauses equally frequently whether the chase is up or down an incline.

(D)If、when a beetle pauses、it has not gained on the insect it is pursuing、the beetle generally ends its pursuit.

(E)The faster a beetle pursues an insect fleeding directly away from it、the more frequently the beetle stops.

答案是：(B)
想請各位高手幫忙(B)跟(C)兩個答案意思不是差不多嗎？選那個好阿？

[Penny Lee]

(B)In pursuing a swerving insect、a beetle alters its course while running and its pauses become more frequent as the chase progresses.

B說甲蟲會隨著獵物方向的改變而隨是變更它的方向(此點排除是visual的問題),可是隨著追逐得進行,它休息的時間也變的頻繁(此點支持-->因為無法maintain pace的問題)

(C)In pursuing a moving insect、a beetle usually responds immediately to changes in the insect's direction、and it pauses equally frequently whether the chase is up or down an incline.

C說甲蟲會立刻反應獵物的方向(支持不是visual的問題),甲蟲每每暫停的時間都是一樣的(如果都是一樣,就無法證明是不是因為無法調整步調才停下來休息的)

[celivia]

(B)In pursuing a swerving insect、a beetle alters its course while running and its pauses become more frequent as the chase progresses.

B說甲蟲會隨著獵物方向的改變而隨是變更它的方向(此點排除是visual的問題),可是隨著追逐得進行,它休息的時間也變的頻繁(此點支持是無法maintain pace的問題)

(C)In pursuing a moving insect、a beetle usually responds immediately to changes in the insect's direction、and it pauses equally frequently whether the chase is up or down an incline.

C說甲蟲會立刻反應獵物的方向(支持不是visual的問題),甲蟲每每暫停的時間都是一樣的(如果都是一樣,就無法證明是不是因為無法調整步調才停下來休息的)

但OG的解釋是說B支持了第二個假設
C則兩個假設都不支持也不反駁
我也搞不太懂

[aerobert]

就是這樣在奇怪阿～看OG的解釋看不懂
感覺有講等於沒講

[A級垂耳兔]

因為題幹是alternative hypothesis ...也就是兩個假設只能一個存在...
故答案只要support其中一個或是weaken其中一個就好了.....
不用support其中一個同時又weaken另一個

答案(B)證明暫停是因為壁虎腦子無法快速處理視覺變化...support其中一個理論

答案(C)壁虎追逐獵物在轉向的時候可以快速反應(證明第二個假設無關)...而且跑上坡和下坡停止的頻率一樣(證明第一個假設無關)
所以答案(C)等於是把兩個假設都否決了....無法達到題目的要求.....

[lucyyeh]

今天早上起床後一路很順的Review CR直到這題

頭腦頓時成醬糊

OG Explanation有句讓人費解
.... remembering that information that supports one hypothesis must necessarily detract form the other.

所以我並不同意樓上說支持一個或弱化一個即可的做法
而且我第一次做的時候
對(C)選思路也是跟Penny類似 既然Tiger beetle 可以responds immediately to changes in the insect's direction，那牠的vision應該沒有什麼問題，搞不好就是"while running"太累，所以才會"pause"---->
不過以上想法可能都犯了"想當然爾"的毛病是吧?OG的解釋有句我覺得至為關鍵"the beetle could be stopping for either reason"
不過話說回來
就句意來說，(B)選跟(C)在and 前有什麼差別，不都是追一隻會動的蟲然後改變方向? 只有在對pause frequency的描述不同 (C)選因為pause frequency都一直相同，那麼對一隻會動的反應既然沒有影響pause frequency，就不能解釋上述的兩個假說。

可是(B)選又是怎麼解釋了vision說而否定了tiredeness說呢?
我同意對一隻會動的蟲，tiger beetles無法及時update visual information，可是這個選哪裡裡用有讓tiredeness less good的原因
一直改變方向Tiger beetle不會累嗎?不會跑不動嗎而需要增加pause frequentcy.但(B)選至少解釋了一種說法是吧?

無路可走，還是選(B)

不知道大家覺得如何?


P.S Tiger beetle如下，我看不出什麼道理來
http://en.wikipedia.org/wiki/Tiger_beetle

[lucyyeh]

今天聽到一個解釋，說OG是錯的

題幹明明寫的很清楚要"support one of two"and"determine"the other結果解釋又解出不出來--真是沒道理

今天問的結果:
(B)選 In pursuing a swerving insect (會動來動去的蟲), a beetle alters its course while running ---> 表示它的視覺沒問題，如果蟲的視力會反應不過來，那應該沒辦法偵測到而改變路徑，所以否定第二種假說(OG寫加強)，另外its pauses beccome more and frequent as the chase progresses. --->越來越需要暫停，就表示越跑越難maintain their pace，要休息，所以支持了假說一。


我覺得以上解釋比較合理，所以提供給大家參考，希望對大家有幫助，

[dibert8]

(B) 支持第二個假設(來不及處裡視覺資訊而暫停)似乎可以理解:
追昆蟲時變換以調整方向(因為來不及處裡視覺資訊必需時常修正),追越久暫停頻率越高(還在追表示還沒追丟,可能得失心切,增加暫停來提升視覺資訊處理的效率i.e. 追的效率);暫停是為了處裡視覺資訊而不是調整體力.

(C) 看起來支持第一個假設(調整步伐而暫停):緊隨昆蟲逃逸方向而變換路徑(所以不是來不及處裡視覺資訊),不管昆蟲怎麼飛都定時暫停以調整步伐(這就好像長跑選手調整呼吸頻率一樣,不管上坡,下坡,都維持固定的呼吸頻率) => 可是這樣追得到嗎?

(B) 不在我們平常認知的知識範圍(我們填飽肚子不需要去追獵物),而 (C) 比較容易確認(很多人都知道怎麼練習長跑,但這對於追補獵物卻沒什麼助益),所以 (B) 不容易選到.從這裡可以看到 CR 題目的設計,與刁鑽的一面.

[dibert8]

tiger beetle (八星虎甲蟲) 因為飛太快,眼睛接收到的光子不足以形成影像,所以追捕獵務時,必需暫停,看清楚以後再繼續追.
康乃爾大學的昆蟲學教授 Cole Gilbert 是這方面的專家: http://www.news.cornell.edu/releases/Ja ... e.bpf.html

[lucyyeh]

感謝dilbert8這麼詳細的解說，這證明了OG是對的，看來AT出考題都不會出違反事實的選項出來

[lucyyeh]

今天做到一題同題幹PP，選項有點不同，貼給大家參考
PP Test 1 - 24.

Tiger beetles are such fast runners that they can capture virtually any nonflying insect. However, when running toward an insect, the beetles intermittently stop, and then, a moment later, resume their attack. Perhaps they cannot maintain their pace and must pause for a moment's rest; but an alternative hypothesis is that while running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop.

Which of the following, if discovered in experiments using artificially moved prey insects, would support one of the two hypotheses and undermine the other?

(A) When a prey insect is moved directly toward a beetle that has been chasing it, the beetle immediately turns and runs away without its usual intermittent stopping.
(B) In pursuing a moving insect, the beetles usually respond immediately to changes in the insect's direction, and pause equally frequently whether the chase is up or down an incline.
(C) The beetles maintain a fixed time interval between pauses, although when an insect that had been stationary begins to flee, the beetle increases its speed after its next pause.
(D) If, when a beetle pauses, it has not gained on the insect it is pursuing, the beetle generally ends its pursuit.
(E) When an obstacle is suddenly introduced just in front of running beetles, the beetles sometimes stop immediately, but they never respond by running around the barrier.
答案C

[vantreal]

(C) The beetles maintain a fixed time interval between pauses, although when an insect that had been stationary begins to flee, the beetle increases its speed after its next pause.

這個是和vision 無關for sure,
但是我覺得和第一個 hypothesis說的
"they cannot maintain their pace and must pause for a moment's rest." 也有點出入.
因為hypothesis說they cannot maintain their pace, 但這裡是說they maintained a fixed time interval, 然後之後可以increase its speed.
不是就等於weaken掉第一個hypothesis嗎?

weaken第一個, 然後和第二個vision無關, 這這這.....................
(大概是我理解能力太差, 請大家們動動腦吧!!)

[vantreal]

剛剛在猜,
會不會是因為when an insect that had been stationary begins to flee, the beetle increases its speed after its next pause.

靜止的突然逃掉了, 然後bettle的有看到, 所以vision上bettle是ok的.

[dibert8]

1. The beetles maintain a fixed time interval between pauses
2. the beetle increases its speed after its next pause
=> 不像是在調整腳步,比較像短跑選手的爆發; 固定時間就停下來,因為必須先處理視覺資訊.固定時間飛得越快,追的距離越長,能不追丟,表示這段時間內都看得清楚.如果是調整體力,應該不會在間隔時間內的距離越飛越長.

3. although when an insect that had been stationary begins to flee 即使停著的獵物準備起飛逃逸
=> 飛一段時間看不見了所以要暫停一下,即使牛肉就在眼前.看清楚了加快追逐,不然就被跑掉了.

漏了一個必要條件: 不管飛得快慢, beetles 在固定時間內收集到的資訊量是一樣多的.這個必要條件和前面那題不太相容,但我們確實不知道在追的過程中發生什麼情況(i.e. 隱藏的必要條件).這裡可以發現 GMAT 對"必要條件"是不負責的.

[lucyyeh]

呵呵~這題好像換了選項就需要新的解釋了


下圖表示甲蟲和獵物的飛行行為(C選情境)
---->----- (飛) ~~(停) X(獵物開始逃的起點)

甲蟲飛行行為 ----->----- ~~ ----->----- ~~ ----->----- ~~----->-----
獵物飛行行為 ~~~ X ----------->----
------------------------蟲開始飛時，甲蟲並沒有看到，pause後才看到才能去追

支持了假說二

但接下來可能跟樓上說的一樣
是說they maintained a fixed time interval, 然後之後可以increase its speed. 不是就等於weaken掉第一個hypothesis嗎?





--------下面是我覺得很矛盾的地方，不想讓自己矛盾的不要看下去-------------

這也可以解釋為甲蟲追到一半就"翅"軟，必須暫停休息

PP-Test1-24 的正確(C)選寫的time interval
剛好跟OG11th-DiagnosticTest-Q25正確(B)選Frequency是相反狀態