生物学
侧膣
When they go through the birth canal, they get exposed to the entire bacteria population of their mother's vaginal and GI microbiomes.
CNN: Where do allergies come from?
英汉双解词典包含3185865条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。