Whereas in mammals the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, in birds the tubes form a random pattern.

(A) Whereas in mammals the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, in birds the tubes

(B) Whereas the tiny tubes for the conveying of nutrients to bone cells are arrayed in mammals in parallel lines, birds have tubes that

(C) Unlike mammals, where the tiny tubes for conveying nutrients to bone cells are arrayed in parallel lines, birds’ tubes

(D) Unlike mammals, in whom the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, the tubes in birds

(E) Unlike the tiny tubes that convey nutrients to bone cells, which in mammals are arrayed in parallel lines, in birds the tubes

选项分析：

(A)Whereas in mammals the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, in birds the tubes

【正确】 “in mammals the tiny tubes……are arrayed in parallel lines”和“in birds the tubes form a random pattern”两个主谓结构用“whereas”连接，形成合理的转折关系。表意清晰且句式工整。

【大意】 在哺乳动物中传送养分的细管以平行线排列，而在鸟类中细管形成了随机的样式。定语从句“that convey nutrients to bone cells”对“tiny tubes”进行了简洁而明确的就近修饰。

(B)Whereas the tiny tubes for the conveying of nutrients to bone cells are arrayed in mammals in parallel lines, birds have tubes that

【错误1】 句子意思：当平行结构真正将语法功能一致，逻辑含义对等的对象平行在一起时，可以非常准确、合理、平衡地描述事物的不同侧面，表以上具有优越性。虽然“whereas”引导的从句不一定非要和主句十分对仗，但(A)中“in mammals the tiny tubes……”和“in birds the tubes……”优于句式平行，表意明显优于(B)。

【错误2】 简洁明了：在GMAT语法题中表达同一个意思时，简洁性从高到低依次为动词、形容词和副词、一般名词、动名词(简称VANing原则：V——verb，A——adj.或adv.，N——noun，ing——动名词)，因此(A)中动词“convey”简洁性优于本选项的“the conveying of”。

(C)Unlike mammals, where the tiny tubes for conveying nutrients to bone cells are arrayed in parallel lines, birds' tubes

【错误】 比较结构：“unlike”语法上比较对象为“mammals(哺乳动物)”和“birds' tubes(鸟的细管)”，但两者实际上并不可比。

(D)Unlike mammals, in which the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, the tubes in birds

【错误】 比较结构：见(C)。

(E)Unlike the tiny tubes that convey nutrients to bone cells, which in mammals are arrayed in parallel lines, in birds the tubes

【错误】 修饰成分：“which in mammals are arrayed in parallel lines”本意上跳跃修饰“the tiny tubes”，但语法上更倾向于就近修饰“bone cells”，因此修饰关系不够明确。

解题思路：

“unlike”比较的对象应平行可比，于是立即排除(C)、(D)。

(E)中修饰关系不明确，排除。

比较(A)、(B)，(A)未发现任何语法错误，且简洁性优于(B)。

因此选择(A)。