Number one, there is such a thing as a skeletal stem cell -- a skeletal stem cell that builds up the entire vertebrate skeleton, bone, cartilage and the fibrous elements of skeleton, just like there's a stem cell in blood, just like there's a stem cell in the nervous system.
第一，假設真有这样的骨干细胞-- 构造了整个脊椎骨架， 骨头、软骨组织、 以及骨架周边的支持物， 就像是血液中的造血干细胞， 就像是神进系统中的神经干细胞。