第24题: [简答题]自然界开始了一次新的实验。人类不再只是能适应某一特定的环境，而是获得了能适应任何环境的能力。他们分散到世界各地，在迁移中不断变化，直到成为在地球上分布最广的物种。人类在身体和文化方面都适应他们迁入的新环境。居住在赤道附近的人为了在强烈日光下保护自己，渐渐地有了黑色皮肤。迁移到寒冷地带的人为了利用阳光合成维生素D，渐渐地有了较为白皙的皮肤。住在寒冷而干燥地区的人们长得矮胖，以便保存热量；住在干燥而炎热地区的人们长得高瘦，以便使热量容易散发。 参考答案:
Nature began a new experiment. Instead of adapting to a specific environment, man has the capacity to adapt himself to any specific environment. They spread throughout the globe, changing as they moved, until they became the most widely distributed species on the earth. Man adapted physically as well as culturally to the new surroundings into which he moved. People who lived near equator developed dark skin to protect themselves from strong sunlight; people who moved to colder climates developed light skin to take advantage of the sunlight for the synthesis of vitamin D; people in cold dry climates became stocky to conserve heat. People in hot dry climates tended to become tall and thin to dissipate heat.
