求众高手进 BT题 GWD24套版第11套里的一道

mycontrol01

GWD24套版第11套里的文章
    Researchers studying how genes control animal behavior have had to deal with many uncertainties. In the first place, most behaviors are governed by more than one gene, and until recently geneticists had no method for identifying the multiple genes involved. In addition, even when a single gene is found to control a behavior, researchers in different fields do not necessarily agree that it is a “behavioral gene.” Neuroscientists, whose interest in genetic research is to understand the nervous system (which generates behavior), define the term broadly. But ethologists ― specialists in animal behavior― are interested in evolution, so they define the term narrowly. They insist that mutations in a behavioral gene must alter a specific normal behavior and not merely make the organism ill, so that the genetically induced behavioral change will provide variation that natural selection can act upon, possibly leading to the evolution of a new species. For example, in the fruit fly, researchers have identified the gene Shaker, mutations in which cause flies to shake violently under anesthesia. Since shaking is not healthy, ethologists do not consider Shaker a behavioral gene. In contrast, ethologists do consider the gene period (per), which controls the fruit fly’s circadian (24 hour) rhythm, a behavioral gene because files with mutated per genes are healthy, they simply have different rhythms.

The primary purpose of the passage is to

A.    summarize findings in an area of research
B.    discuss different perspectives on a scientific question
C.    outline the major questions in a scientific discipline
D.    illustrate the usefulness of investigating a research topic
E.    reconcile differences between two definitions of a term


答案给的是B， 我选的C。我觉得文章第一句已经说明了had to deal with many uncertainties， 而且接下来是In the first place粗略讲第一点…In addition 详细讲了第二点。 文章篇幅虽然大多在写第2点，但文章的目的该怎么判断呢？我觉得还是该说明作者观点的！

而且此类情况我记得遇到过两三次了，即是文章开头讲的大范围，后面详细讲一个小点 该选什么呢》是大范围的情况还是小点呢？
刚翻了下OG12，阅读部分第25题（讲蛇的重力适应那文章），虽然作者大篇幅都是对比，但其实还是为了说明陆地蛇的适应而非海蛇。这个文里对比的2种科学家态度的也类似吧，应该是说明不确定性的！？