大全III－19

Identical twins tend to have similar personalities; if environment outweighs heredity in personality development, twins raised together should presumably have more similar personalities than those raised apart. A recent study of identical twins in both situations measured 11 key traits through a questionnaire, and concluded that 7 of the 11 are primarily products of heredity.

Which of the following, if established, would cast the most doubt on the study’s results?

(A) Fewer than half of the pairs of twins studied were raised separately.

(B) The ages of all of the twins studied fell within a 10-year range.

(C) Some of the traits that the study attributed to heredity developed in the separately raised twins because those pairs all grew up in similar families.(A)

(D) Although over half the traits measured were determined to be linked to heredity, the nature of those traits varied widely.

(E) The 11 traits that were measured constitute a representative sample of larger, generally accepted pool of key personality traits

答案是C，为什么不选A呢？

谁帮我分析一下好么？谢谢：）

C说：在相似的环境中（虽然不同,但很相似）培养，研究将这些相同的特征归属于遗传特征，可是根据原文：在相同或相似的环境中，环境也可影响个性特征，这样，在调查中就无法判定，这些相同的特征到底是属于环境造成的，还是遗传造成的，从而削弱。

A是既没削弱也没加强:有一小半在分离的不同家庭培养，一大半的相同家庭培养,有一大半的性格相同,从而使调查结论认为一大半性格是遗传控制的.

需要强调的:我觉得题不好,出题不理解遗传生物学,他把可遗传的个性特征和后添环境特征混在一起,意思是说,可遗传的个性特征是可以根据环境的变化而改变的,可是可遗传的个性特征---基因在同代是不可改变的