文档介绍：Directions:
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 geneticist.
As James Fowler,
professor
of
medical genetics
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 manymechanisms working
together
that _(12)_us
in choosing
genetically
similar friends_(13)_ ”functional
Kinship ” of being friends
with_(14)_!
Oneof
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 exp
lain 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.
[A] when [B] why [C] how [D] what
[A] de