随体DNA在CsCl梯度离心时有较高的浮力密度,主要是由于其组成中() ["A、A-T含量高","B、G-C含量高","C、重复顺序高","D、重复顺序低"]
选择齿轮的材料为() ["A、08F","B、45钢","C、65Mn"]
大脑表皮细胞中终止于桥粒极的中间纤维是() ["A、张力丝","B、结蛋白丝","C、波形丝","D、神经丝"]
过共折钢的淬火加热温度应选择在() ["A、Ac1+30~50c","B、Ac3+30~50摄氏度","C、Accmccm以上"]
有丝分裂中期最主要的特征是() ["A、染色体排列在赤道面上","B、纺锤体形成","C、核膜破裂","D、姐妹染色体分开"]
英译中(Translate):uniport carrier()