exoperigon

例句：

1. 1. The embryonic development of the plant is divided into three main stages: the root, the shoot, and the exoperigon.
   植物胚胎发育分为三个主要阶段：根、茎和外胚层。
2. 2. The outer layer of the skin protects the underlying tissues from external factors.
   皮肤的外层保护着下面的组织免受外界因素的影响。
3. 3. The outer layer of the skin is responsible for regulating body temperature and moisture balance.
   皮肤的外层负责调节体温和保持水分平衡。