This conclusion is also suggested by the fact that people who live in close contact with each other, but who are not related at all are likely to have similar degree of intelligence. (Passage One)

【参考答案】

还有一个事实也可以证实这样的结论，那就是，两个毫不相干却在生活中关系密切的人，他们的智力水平可能也会相似。