exophloem

例句：

1. 1. The plant's exophelium is a protective covering that protects the plant from predators.
   植物的外皮是一层保护覆盖，可以保护植物免受捕食者的伤害。
2. 2.The scientist observed the exophelium of the butterfly and noted its unique color pattern.
   科学家观察到蝴蝶的外皮层并注意到其独特的颜色图案。
3. 3.The researcher studied the exophelium of various species to understand their adaptations to their environment.
   研究者研究了各种物种的外皮层以了解它们对环境的适应方式。