下列生物体内物质中,基本组成单位相同的一组是()
A. 纤维素和维生素
B. 糖原和抗原
C. 质粒和中心粒
D. 胰岛素和胰高血糖素
变压器空载运行时,由于二次侧没有电流,故其变比为零。
A. 正确
B. 错误
在两片金属导体中间保持一定距离组成的封闭物体叫电容器。
A. 正确
B. 错误
Which two are the prerequisites to enable Flashback Data Archive?() (Choose two.)
A. Database must be running in archivelog mode.
B. Automatic undo management must be enabled.
C. Undo retention guarantee must be enabled.
D. The tablespace on which the Flashback Data Archive is created must be managed with Automatic Segment Space Management (ASSM).