水在常温下是液体，在通电条件下，发生如下的化学反应：2H₂O $\underset{\_}{\underset{\_}{通电}}$ O₂+2H₂，该反应属于（   ）

眼球结构中具有折射光线作用的主要结构是（　　）

在图中所示的电路中，当滑动变阻器的滑动触片向b端移动时（   ）

根据短文内容，选择正确答案。
B
    I'm Kate from the UK. I'm in the Chinese club in our school. I like Chinese and I think it's interesting. My Chinese is very good. I can tell and write stories in Chinese. My favorite writer (作家) is Mo Yan from China. Now let me tell you something about my favorite writer and his family.     Mo Yan's real (真的) name is Guan Moye. Mo Yan is his pen name. This year Mo is 57 years old. His birthday is on February 17th. Mo writes stories very well. He can also write with his left hand (左手). Mo has a daughter. Her name is Guan Xiaoxiao. The girl can also write stories but she can't write with her left hand.

在证明DNA是遗传物质的实验中，赫尔希和蔡斯分别用³²P和³⁵S标记噬菌体的DNA和蛋白质，在下图中标记元素所在部位依次是（   ）