扫描二维码，直接登录
题库 / Prep2007E1-RC-25
In terrestrial environments, gravity places special demands on the cardiovascular systems of animals. Gravitational pressure can cause blood to pool in the lower regions of the body, making it difficult to circulate blood to critical organs such as the brain. Terrestrial snakes, in particular, exhibit adaptations that aid in circulating blood against the force of gravity.
The problem confronting terrestrial snakes is best illustrated by what happens to sea snakes when removed from their supportive medium. Because the vertical pressure gradients within the blood vessels are counteracted by similar pressure gradients in the surrounding water, the distribution of blood throughout the body of sea snakes remains about the same regardless of their orientation in space, provided they remain in the ocean. When removed from the water and tilted at various angles with the head up, however, blood pressure at their midpoint drops significantly, and at brain level falls to zero. That many terrestrial snakes in similar spatial orientations do not experience this kind of circulatory failure suggests that certain adaptations enable them to regulate blood pressure more effectively in those orientations.
One such adaptation is the closer proximity of the terrestrial snake's heart to its head, which helps to ensure circulation to the brain, regardless of the snake's orientation in space. The heart of sea snakes can be located near the middle of the body, a position that minimizes the work entailed in circulating blood to both extremities. In arboreal snakes, however, which dwell in trees and often assume a vertical posture, the average distance from the heart to the head can be as little as 15 percent of overall body length. Such a location requires that blood circulated to the tail of the snake travel a greater distance back to the heart, a problem solved by another adaptation. When climbing, arboreal snakes often pause momentarily to wiggle their bodies, causing waves of muscle contraction that advance from the lower torso to the head. By compressing the veins and forcing blood forward, these contractions apparently improve the flow of venous blood returning to the heart.
The passage provides information in support of which of the following assertions?
The disadvantages of an adaptation to a particular feature of an environment often outweigh the advantages of such an adaptation.
An organism's reaction to being placed in an environment to which it is not well adapted can sometimes illustrate the problems that have been solved by the adaptations of organisms indigenous to that environment.
The effectiveness of an organism's adaptation to a particular feature of its environment can only be evaluated by examining the effectiveness with which organisms of other species have adapted to a similar feature of a different environment.
Organisms of the same species that inhabit strikingly different environments will often adapt in remarkably similar ways to the few features of those environments that are common.
Different species of organisms living in the same environment will seldom adapt to features of that environment in the same way.
题目分析：
题目释义：
细节题目
考点：
应用（Application）
旨在考察我们对文章细节的深度认知，并达到可以应用总结的地步。
这个题目很难定位，即是要对于全文的细节做一个了解，然后选择。这道题的错误选项基本都是文章中没有提到的。
选项分析：
A选项：一个对特定环境特征的适应性的缺点远大于这个适应性的优点。文中没有提到过适应性的优缺点问题，这个选项属于无中生有。
B选项：Correct。一个生物体在被放到一个不适应的环境时有时会说明那些被适应这个环境的适应性所解决的问题。这个选项可以定位在第二段中，水蛇被拿出水自然适应不了陆地的重力系统，但是与水蛇有相似特征的陆地蛇并没有死，这就说明了陆地蛇必然有适应性存在。并且这个适应性解决了这个重力的问题。与该选项的意思相符。
C选项：生物体对特定环境的独特特征的适应性的有效与否只能通过这个生物群体的其他物种适应的不同环境的同样特征的有效性来检验。在选择中，尽量避开文中没有明显提及的“极端”词汇。比如这个选项的“only”。另外，这个选项的内容在文中也没有明显涉及。
D选项：同种类的生物体居住在极为不同的环境中通常对这些环境的为数不多的相同点有着显著的相同的适应方法。文中没有提及这个选项的内容，无中生有。
E选项：不同物种的生命体在相同的环境下不会用同样的方法适应环境的特征。这个选项没有根据。文中也没有提及说不同物种的适应方法。
C选项是在说：如果要展现陆栖蛇的adaptation是否有效，就必须拿他和其他物种适应其他环境的有效性来检验（譬如水蛇对水的适应这件事）。首先only太过绝对，其次文章中并不是这么说的，文章中是说如果要体现陆栖蛇的adaptation是个什么情况，最好是拿水蛇在陆地上不适应这件事来检验，而非水蛇对水的适应这件事。
不能出现新信息
第一段说了陆栖蛇有adaptation，第二段用一个例子说了和水栖蛇相比，陆栖蛇的adaptation是个什么情况，第三段才正式介绍这个adaptation是什么.
正确B选项：The problem confronting terrestrial snakes is best illustrated by what happens to sea snakes when removed from their supportive medium.
C选项：文中没提到：effectiveness of an organism's adaptation; only 极端词；【尽量避免极端词！！】
错选D选项：文中只提到物种适应不同环境，没提适应相同的环境；
terrestrial陆生的
第一段说了陆栖蛇有adaptation，第二段用一个例子说了和水栖蛇相比陆栖蛇的adaptation是个什么情况，第三段才正式介绍这个adaptation是什么.
choice B直接概括了P2的中心思想：The problem confronting terrestrial snakes is best illustrated by what happens to sea snakes when removed from their supportive medium. 陆蛇所面对的问题可以通过当水蛇离开支持媒介面对的来解释
choice C:
生物体对于它所在环境某一个特征的适应性的有效性，只能通过检验其他物种对于一个不同环境的相似特征的适应性的有效性。1）only过于绝对 2）全文没有提到不同环境之间的相似特征（陆地、海洋是完全不同的环境，之间没有相似性）
C 在选择中，尽量避开文中没有明显提及的“极端”词汇。比如这个选项的“only”。
避开极端词！！！！
A选项：本文提到怎样适应环境，没提缺点；
B选项：The problem confronting terrestrial snakes is best illustrated by what happens to sea snakes when removed from their supportive medium.
C选项：文中没提到：effectiveness of an organism's adaptation; only 极端词；
D选项：文中只提到物种适应不同环境，没提适应相同的环境；
E选项：没提到不同物种很少用同样方式适应同样环境
本文大意：T蛇，海蛇，A蛇。开头说T蛇适应了一些重力对于血液的影响，而它所面临的问题在海蛇身上可以体现。海蛇在水中，由于水讲中立中和，海蛇全身的血液量是一样的，然后当海蛇从水中出来后，身体中间一下的血液迅速流向尾部，而其脑袋又在身体中间部位，以至于脑部没有血液；而这点上来说，T蛇表现得更好一些，因为｛它已经适应在不同方向上调节血压｝｛它的脑部和心脏距离很近也是它的一个适应性的表现“｝｛对于在树上生活的A蛇来说｝心脏和脑袋的距离只有身体的15%，心脏的血液很容易供给脑部，而血液流到尾部再流回来的时间变长。它很好的适应血液循环的问题，通过间歇性的停下身体，摇晃尾巴，收缩肌肉，｛促使血液流回心脏和大脑｝。
An organism's reaction to being placed in an environment to which it is not well adapted can sometimes illustrate the problems （问题）that have been solved by （被解决）the adaptations of organisms indigenous to that environment.
如果C没有only是对的是吗？
indigenous这个单词意思忘了
细节2，明显的推导题