题目内容：
根据以下材料回答题：Directions：Read the following text. Choose the best word for each numbered blank and mark A, B, C or D on ANSWER SHEET 1. （10 points）The idea that some groups of people may be more intelligent than others is one of those hypotheses that dare not speak its name. But Gregory Cochran is___(1)___to say it anyway. He is that___(2)___bird, a scientist who works independently ___(3)___ any institution. He helped popularize the idea that some diseases not ___(4)___ thought to have a bacterial cause were actually infections, which aroused Much controversy when it was first suggested.
___(5)___ he, however, might tremble at the ___(6)___of what he is about to do. Together with another two scientists, he is publishing a paper which not only ___(7)___that one group of humanity is more intelligent than the others, but explains the process that has brought this about. The group in___(8)___are a particular people originated from central Europe. The process is natural selection.
This group generally do well in IQ test, ___(9)___12-15 points above the ___(10)___value of 100, and have contributed ___(11)___to the intellectual and cultural life of the West, as the ___(12)___of their elites, including several world-renowned scientists, ___(13)___. They also suffer more often than most people from a number of nasty genetic diseases, such as breast cancer. These facts, ___(14)___, have previously been thought unrelated. The former has been ___(15)___ to social effects, such as a strong tradition of___(16)___ education. The latter was seen as a （an） ___(17)___of genetic isolation. Dr. Cochran suggests that the intelligence and diseases are intimately ___(18)___ . His argument is that the unusual history of these people has ___(19)___ them to unique evolutionary pressures that have resulted in this ___(20)___ state of affairs.请选择(1)处最佳答案（ ）。 A．selected
B．prepared
C．obliged
D．pleased
参考答案：
答案解析：