1. Each barbule is made up of many smaller branches called barbicles.
每个冠毛细丝由许多称为冠毛分枝的小分支组成。

2. The barbules on a bird's feathers interlock to create a smooth and aerodynamic surface.
鸟羽毛上的冠毛细丝相互锁定，创造出光滑且具有空气动力学特性的表面。