A. dependent on simpler mental activity B. found in animals as well as man C. farther up the evolutionary scale D. present in animals on the basis of much evidence 参考答案:B 答案解析:参见第四段;“make this last case less convincing than the one which follows"--i.e.,the crow.
第23题: [单项选择]妊娠期用药不当,可能致胎儿娩出后继续受到药物作用的阶段是 A. 妊娠第14天~1个月 B. 妊娠第20天~3个月 C. 妊娠14周~6个月 D. 妊娠6~9个月 E. 产前 参考答案:E 答案解析:[解析] 妊娠14周后,胚胎各组织器官分化大体完成,仅中枢神经系统或生殖系统可能致畸。但致畸作用强及持续时间长的药物,可影响胎儿的生理功能和发育成长。