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[Reading Comprehension]
试题详情
文章：
| Line | 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 | |
| (5) | 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 | |
| (10) | 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 | |
| (15) | 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 | |
| (20) | 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 | |
| (25) | 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 | |
| (30) | 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 | |
| (35) | 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 | |
| (40) | 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 | |
| (45) | apparently improve the flow of venous blood |
| returning to the heart. |
题目：
The author suggests that which of the following is a disadvantage that results from the location of a snake’s heart in close proximity to its head?
选项:
A、A decrease in the efficiency with which the snake regulates the flow of blood to the brain
B、A decrease in the number of orientations in space that a snake can assume without loss of blood flow to the brain
C、A decrease in blood pressure at the snake’s midpoint when it is tilted at various angles with its head up
D、An increase in the tendency of blood to pool at the snake’s head when the snake is tilted at various angles with its head down
E、An increase in the amount of effort required to distribute blood to and from the snake’s tail
答案:
E
提问：
请老师解释一下答案D的错误原因
解答：
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阅读1006
提问：
请老师解释一下答案D的错误原因
解答：
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阅读1007
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