gastrulae

例句：

1. 1. The embryo is the first stage of a developing organism.
   胚胎是发展生物的第一个阶段。
2. 2. During early development, the gastrulae are the basic structures of the future body.
   在早期发育过程中，胃泡是未来身体的基本结构。
3. 3.The gastrulae are surrounded by fluid and gradually develop into the adult form.
   胃泡被液体包围，并逐渐发育成成年形态。