胎盘

例句：

1. 1. The fetus isprotected by the amniotic sacand the umbilical cord,which are part of the mother'suterus.
   胎儿被羊水和脐带保护，它们是母体子宫的一部分。
2. 2. The placenta plays a crucialrole in the development of the fetusduring pregnancy.
   胎盘在孕期胎儿发育中起着至关重要的作用。
3. 3. During labor, the placenta releases nutrients to nourish the baby.
   分娩期间，胎盘释放养分以滋养婴儿。