你没看过2008年考研英语阅读吗?《美国人的身高已经达到上限》“就算人类已经直立行走已经几百万年了,我们的脚和背部继续对抗着巨大的压力,这些压力来源于双足直立的姿势和巨大的肢体。有一些限制是个体器官的基因结构导致的。”“Moreover, even though humans have been upright for millions of years, our feet and back continue to struggle with bipedal posture and cannot easily withstand repeated strain imposed by oversize limbs. ―There are some real constraints that are set by the genetic architecture of the individual organism.”I