extraembryonic vessel

例句：

1. 1.The extraembryonic vascular system plays a crucial role in the development of the embryo.
   胚胎外血管系统在胚胎发育中起着至关重要的作用。
2. 2. During the process of embryonic development, the extraembryonic vascular system is responsible for delivering nutrients and oxygen to the developing fetus.
   在胚胎发育过程中，胚胎外血管系统负责将营养物质和氧气输送给正在发育的胎儿。
3. 3. The extraembryonic vascular system is an essential component of the placenta, which provides oxygenand nutrients to the fetus during pregnancy.
   胚胎外血管系统是胎盘的重要组成部分，它在怀孕期间为胎儿提供氧气和营养。