限制性内切酶的催化活性比非限制性内切酶的催化活性低
查看答案
嘌呤核苷酸的合成顺序是，首先合成次黄嘌呤核苷酸，再进一步转化为腺嘌呤核苷酸和鸟嘌呤核苷酸
A. 对
B. 错
It was reported that the earthquake was the most ____to have struck that area in fifty years.
A. special
B. powerful
C. favorite
D. exciting
It took the experts several months to decide on the ____for the new airport.
A. source
B. earth
C. site
D. character
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