Flies evolve to be smarter only in the labs fundamentally because______. A．flies can adapt to the environment without learning B．the cost of learning in the wild is too huge to bear C．they may get some diseases as a byproduct in nature D．the lab conditions allow them to learn better
A. A．flies B.the C.they D.the
【参考答案】
B 属信息推断题。文章第六段第二、三句讲到果蝇可以进化得更聪明，但只有在实验室中才会这样。第四句又说到，在大自然......