已知函数f（x）=5^x，g（x）=ax²﹣x，若f（g（1））=1，则a=（　　）

周朝封建卫、鲁时，命二国“皆启以商政，疆以周索”，封建晋国时，命晋国“启以夏政，疆以戎索”。据查，商政、夏政是商、夏两朝对统治民族因其故俗制定的统治制度。这说明周初（   ）

细胞增殖是生物体内一项重要的生命活动。下图是某高等植物细胞有丝分裂周期图，请据图分析下列说法不正确的是     （    ）

    Last year, some groups of students in their community made a survey about “How do people spend their free time?” The following diagrams show some results of it:

    Diagram (1): Hours for people of different ages who surf the Internet in a week.

    Diagram (2): Different days people go to the library. ( library attendance )

    Diagram (3): Different sports people like.

D (1)                                         D(2)

D (3)