PTN的交换核心是（） ["数据包","SDH帧","ATM信元","PDH帧"]
在雌核发育中，精子进入卵内只起刺激卵子发育的作用。
致畸作用
设计文化中的技术从古至今可分为（） ["手工业","制造业","大工业","计算机","新媒体"]
Refer to the exhibit. Which subnet mask will place all hosts on Network B in the same subnet with the least amount of wasted addresses?（） ["255.255.255.0","255.255.254.0","255.255.252.0","255.255.248.0"]
试述乙脑的诊断。
