Nevertheless, in those societies in which matrilineal descent occurs, access to socially powerful positions is mediated through the maternal line of kin. 無論如何，在那些母權宗系遺傳的社會，是由母系親屬來掌握社會上最有權力的地位。
Each haplogroup is defined by set of characteristic mutations on the mitochondrial genome, and can be traced along a person's maternal line to a specific prehistoric woman. 每一個單倍組都是根據線粒體基因組的變化特徵來定義，可以追溯一個人的母系遺傳線索，直到一位特別的史前女性。
The surface generated by a straight line,the generator,passing through a fixed point,the vertex,and moving along a fixed curve,the directrix. 錐面由一條直線，即母線，通過一固定點，即頂點，沿一給定曲線，即準線，連續移動而產生的平面。
