lactin

例句：

1. 1. The baby's growth is closely monitored by the mother's placenta.
   母亲的胎盘密切监控着婴儿的生长。
2. 2.The placenta plays a crucial role in the development of the fetus.
   胎盘在胎儿发育中起着至关重要的作用。
3. 3.The placenta is responsible for transferring nutrients and oxygen to the developing fetus.
   胎盘负责将营养物质和氧气传递给正在发育的胎儿。