primibrach costal

例句：

1. 1. The primibrach of the species is akey to understanding its evolution.
   该物种的初级形态是理解其进化的关键。
2. 2. Primibrachs are often used asbuilding blocks for more complex structures.
   初级结构通常被用作更复杂结构的构建块。
3. 3.The discovery of primibrachs in ancient cave paintings has sparkednew research on human evolution.
   在古代洞穴壁画中发现的初级结构引发了对人类进化的新研究。