这道题正确答案是 B， 我一直觉得是D, 不是特别明白 B 答案为什么 说as effectively as sea snakes can? 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. 20. It can be inferred from the passage that which of the following is true of species of terrestrial snakes that often need to assume a vertical posture? (A) They are more likely to be susceptible to circulatory failure in vertical postures than are sea snakes. (B) Their hearts are less likely to be located at the midpoint of their bodies than is the case with sea snakes. (c) they cannot counteract the pooling of blood in lower regions of their bodies as effectively as sea snakes can. (d) the blood pressure at their midpoint decreases significantly when they are titled with their heads up.

老师，这道题为什么要用现在完成时呢？我觉得用蛇起源于四腿蜥蜴不是持续的动作，也没有持续的影响

请问老师这道题做题思路，可以理解为消序处理吗？比如八个字母排一列，A，B，C三个字母顺序不影响，排列方式为A（8，8）除A（3，3），如果是，为什么这么用？

请问may老师此题思路

请问may老师此题思路

请问may老师此题思路

请问may老师此题思路

请问may老师此题思路

请问may老师此题思路

请问may老师此题思路