【单选题】Which type of mutation leads to sickle cell anemia? Choose the one best answer.
【简答题】设有以下语句:int a=1, b=2, c;c=a^(b<<2) ;执行后,c的值为( )。A. 7 B. 9 C. 8 D. 6
【判断题】经质检部门鉴定不需要返修、可以降价出售的不合格品,不计入废品损失。( )(2017年)
【单选题】U s ing the technique of electrophoresis to study sickle cell anemia, Pauling concluded that ( ).
A.
polypeptides carry the genetic information
B.
the sickle cell gene chemically alters the hemoglobin protein
C.
DNA carries the genetic information
D.
the one-gene-one-enzyme hypothesis was in c orrect
【单选题】Sickle cell anemia is an autosomal recessive genetic disease with a frequency of _______.
【单选题】私人不愿充分提供公共产品是因为无法补偿( )
【单选题】,淬火钢在( )回火时所产生的回火脆性称为第一类回火脆性。
【判断题】锤击焊缝既可以减小焊接变形,还可以减小焊接残余应力。( )