文档介绍：Read the following text. Choose the best word(s) for each numbered blank and mark A, B, C or D on ANSWER SHEET. (10 points)
Though not biologically related, friends are as “related”as fourth cousins, sharing about 1% of genes. That is _(1)_a study, published from the University of California and Yale University in the Proceedings of the National Academy of Sciences, has__(2)_.
The study is a genome-wide analysis conducted _(3)__1,932 unique subjects which __(4)__pairs of unrelated friends and unrelated strangers. The same people were used in both_(5)_.
While 1% may seem_(6)_,it is not so to a icist. As James Fowler, professor of medical ics at UC San Diego, says, “Most people do not even _(7)_their fourth cousins but somehow manage to select as friends the people who_(8)_our kin.”
The study_(9)_found that the genes for smell were something shared in friends but not genes for immunity .Why this similarity exists in smell genes is difficult to explain, for now,_(10)_,as the team suggests, it draws us to similar environments but there is more_(11)_it. There could be many mechanisms working together that _(12)_us in choosing ically similar friends_(13)_”functional Kinship” of being friends with_(14)_!
One of the remarkable findings of the study was the similar genes seem to be evolution_(15)_than other genes Studying this could help_(16)_why human evolution picked pace in the last 30,000 years, with social environment being a major_(17)_factor.
The findings do not simply explain people’s_(18)_to befriend those of similar_(19)_backgrounds, say the researchers. Though all the subjects were drawn from a population of European extraction, care was taken to_(20)_that all subjects, friends and strangers, were taken from the same population.
1. [A] when [B] why [C] how [D] what
2. [A] defended [B] concluded [C] withdrawn [D] advised
3. [A] for [B] with [C] on [D] by
4. [A] compared [B] sought [C] separated [D] connected
5. [A] tests [B] s [C]samples [D] e