在生物学有关实验的叙述中，正确的是（　　）

小龙背着质量为25kg的实验器材从实验楼的一楼上到三楼，又沿着走廊水平走了5m到达实验室．每层楼高3m，小龙对实验器材做功____J．若在搬运实验器材的整个过程中小龙总共做功4500J，则小龙自身体重____kg．（g=10N/kg）

Last night I was getting ready for the coming examination while the noise from my neighbor interrupted me. The noise went on and on. It was too loud that I could hardly pay attention with my study any longer. So I went to my neighbor house and said him, “Excuse me, would you please turn down the TV? I’m preparing for tomorrow’s examination.” Hear these words, his face turned to red. And he said, “OK, I will. I’m very sorry have made so much noise. Just now, the football game was very wonderful. I was too exciting to control myself. I won’t do that again. Good luck in your coming examination.” After that, I got down to his study.

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关于DNA分子的结构及其复制的叙述，错误的是（　　）