translation.en: The white stuff is bone, and these red columns that you see and the yellow cells are cells that have arisen from one single skeletal stem cell -- columns of cartilage, columns of bone coming out of a single cell.
translation.zh: 白色的是骨头， 你看到的红色管狀的，黄色的细胞 都是由一个单独的 干细胞生长而来的—— 软骨、骨组织都来自同一个干细胞，