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【单选题】
细胞冻存的最佳浓度为( )。
A.
5×105 ~ 1 ×106个/ml
B.
5×106 ~ 1 ×107个/ml
C.
5×107 ~ 1 ×108个/ml
D.
5×104 ~ 1 ×105个/ml
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参考答案：
参考解析：
刷刷题刷刷变学霸
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【单选题】用SDS-酚来抽提DNA时，SDS的浓度是十分重要的，当SDS的浓度为0.1%时（）
A.
只能将DNA抽提到水相
B.
只能将RNA抽提到水相
C.
可将DNA、RNA一起抽提到水相
D.
A和RNA都不能进入水相
【单选题】已知 ，则K 2 Cr 2 O，标准溶液浓度为( )
A.
0.01000mol·L -1
B.
0.1000mol·L -1
C.
0.02000mol·L -1
D.
0.2000mol·L -1
【单选题】最佳修复方案是
A.
直接改为活动义齿修复
B.
采用种植固定义齿修复
C.
全冠修复基牙后再改为活动义齿修复
D.
增加前端基牙数再行固定修复
E.
增加前端基牙数目再行固定活动联合修复
【单选题】下列溶液中的Cl - 浓度与50mL1mol/L的AlCl 3 溶液中的Cl - 浓度相等的是（ ）
A.
150ml1mol/L的NaCl溶液
B.
50ml3mol/L的NaCl溶液
C.
150ml3mol/L的MgCl 2 溶液
D.
75ml2mol/L的KCl溶液
【单选题】Long after the 1998 World Cup was won, disappointed fans were still cursing the disputed refereeing (裁判) decisions that denied victory to their team. A researcher was appointed to study the performanc...
A.
The ideal retirement age for an experienced football referee is 35.
B.
Age should not be the chief consideration in choosing a football referee.
C.
A football referee should be as young and energetic as possible.
D.
An experienced football referee can do well even when in poor physical condition.
【单选题】Long after the 1998 World Cup was won, disappointed fans were still cursing the disputed refereeing(裁判) decisions that denied victory to their team. A researcher was appointed to study the performance...
A.
slightly above average
B.
higher than in the 1998 World Cup
C.
quite unexpected
D.
as high as in a standard match