Finally, we know that how intelligent we are and how long we shall live are caused by both environmental and genetic influences. There are experimental designs, using twins, that can find out the extent to which intelligence and mortality are linked because they share environmental and genetic influences.
最后，我们知道我们的智力水平和寿命长短是由环境和基因影响共同造成的。有一些试验性的研究设计，它们使用双胞胎可以发现由于他们具有共同的环境和基因影响，其智力水平和死亡率在多达程度上是联系在一起的。