某亲本DNA分子双链均以黑色表示，以白色表示第一次复制出的DNA子链，以灰色表示第二次复制出的DNA子链，该亲本双链DNA分子连续复制两次后的产物是_刷题宝

题干

某亲本DNA分子双链均以黑色表示，以白色表示第一次复制出的DNA子链，以灰色表示第二次复制出的DNA子链，该亲本双链DNA分子连续复制两次后的产物是（　　）

A：

B：

C：

D：

上一题下一题 0.0难度选择题更新时间:2016-08-20 03:03:24

答案(点此获取答案解析）

C

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数列2，5，11，20，x，47，…中的x值为（）

同类题2

下列不属于旅游规划基本内容的是（）

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同类题4

设实数x，y满足条件

{\begin{matrix} x - y + 2 \leq 0 \\ 2 x - y - 4 \leq 0 \\ x \geq 0, y \geq 0 \end{matrix}

，若目标函数z=ax+by（a＞0，b＞0）的最大值为12，则

\frac{3}{a} + \frac{4}{b}

的最小值为____．

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