细菌的核质DNA构成是()
A.共价闭合环状双链
B.共价闭合单链
C.双链线状
D.单链线状
参考答案:A
--- What a nice party! Thank you for inviting us.
--- ____________. See you.
A.For pleasure.
B.Not so nice.
C.With pleasure.
D.It was a pleasure.
已知反应:X + Y = M + N为放热反应,对该反应的下列说法正确的是[ ]
A.X能量一定高于M
B.X和Y的总能量一定高于M和N的总能量
C.Y能量一定高于N
D.因该反应为放热反应,故不必加热就可发生