hanshipeng

这个题目我细细研究了，发现有两个办法来解决。
一，快速解决，适用于考试时。
题目问的是hypothalamus,那么就到文中第一次出现这个词的地方找。定位到29句。29句处于第二段，看第二段的第一句，The pleiotropy of the five well-studied plant hormones is somewhat analogous to that of certain hormones in animal. 这句话告诉我们pleiotropy of the five well-studied plant hormones和动物中的一些hormones是相似的。hypothalamus hormones 作为动物的hormones 就和 five plant hormones相似了。
二，是我仔细阅读后发现的答案。
来细看文中各种物质间的关系
28行开始：hormones from the hypothalamus in the brain stimulate the anterior lobe （hypothalamus hormones-->anterior）of the pituitary gland to synthesize and release many different hormones（anterior-->different hormones）, one of which stimulates the release of hormones from the adrenal cortex. These hormones have specific (one of the different hormones have specific effects)effects on target organs all over the body. One hormone stimulates the thyroid gland,  
hypothalamus hormones-->anterior-->different hormones have specific effects
其中箭头的层层推导关系，就是文中所谓的 hierarchy吧。

38行开始：Oligosaccharins are fragments of the cell wall released by enzymes（enzymes-->Oligo）: different enzymes release different oligosaccharins. There are indications that pleiotropic plant hormones may actually function by activating the enzymes(pleiotropic plant hormones -->enzymes) that release these other, more specific chemical messengers from the cell wall.
pleiotropic plant hormones -->enzymes-->Oligo

对比下两个箭头推导步骤，发现最后绿色的部分功能一样，都有specific effect。
箭头开始两个红色部分，pleiotropic plant hormones 和hypothalamus hormones 就有可比性了，就是题目的答案。

好像过程很复杂，希望我讲明白了