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.

数学：请问老师这道排列组合怎么解 感觉好复杂

老师，请问这道题思路是什么？

老师，求该题解题思路

DS：说一个女生有一些 tax deductible 其中捐给 b 让她少交了 210 的税，问什么忘记 了求补充，好像是她总收入是多少？ 条件 1：给了税率是 28% 条件 2：给了可税工资（income-deductible）是个五位数。 income*0.28-（income-deductible）*0.28=210 构筑纠结很久 因为题里面说捐给 b 只是 deductible 其中一项，还有其他未知，所以最 后选了 e，现在感觉选 c 请问陆老师，应该选什么？谢谢！

DS：n 是三个不同质数的积，这些质数都在 1-15 之间，问 n 是否＜700？ 其中一个条件是 n 与 70 没有公约数 【补充】 DS：x,y,z 是三个质数，xyz<700？ 条件 1：三个数不大于 14 条件 2：三个数里面有 70 的因数 s 轩辕十四 12/20 【122-补充】 DS：三个整数，问他们的积和一个常数的关系 条件 1：都是小于 15 的质数 条件 2：是 30 的 factor 构筑：这个好像也是个变体吧，好迷啊 ggggggbbbbbb bb 12/20 【122-补充】 DS：Integer p: is p>700? 条件 1：p is product of three prime numbers from 1-15 条件 2：p has no common factor with 70 请问陆老师，这道题选什么？谢谢！

DS：2x^2+bx+8=0，只有一个实数根，求那个字母的值？ 条件 1：b<0 条件 2：lxl>5 x的绝对值 请问陆老师，这道题选什么？谢谢

想请教一下陆老师，我觉得这道题应该是用相似三角形做，看了图觉得应该是用角1和角2相等来证明。但是由题干给的条件，我不知道如何得出角1和角2相等

请问老师图里的这道语法比较，不太明白，如何区分到底比较的是什么呢？谢谢

请问May, 我这道题不知道怎样做？谢谢！

请问May老师，请问这题选5 吗？