【单选题】To: frontofficel From: geraldinebennett Re: Doing our part Dear Mr. Cobalt: I'm writing to you to express my concern about Pascal's reputation as a wasteful company. I'm sure you read the recent lette...
【判断题】DNA的Tm值和A-T含量有关,A-T含量高则Tm高
【简答题】Going to school from 8 am until 5 pm may sound terrible,but Sydney Shaw,a sh grader at the Alain Locke Charter Academy on Chicago's West Side,has come to like it—as well as the extra 20 or so day...
【简答题】桦尺蠖的体色受—对等位基因S和s控制,黑色(S)对浅色(s)是显性。科学家研究发现在19世纪时,曼彻斯特地区SS基因型个体占4%,ss基因型个体占94%,后来随着工业的发展,煤烟污染了环境,s的基因频率降低,S的基因频率提高。请回答上述调查研究说明种群中产生的变异是(),但基因频率的改变是(),由此说明生物进化的方向是由自然选择决定的。
【判断题】DNA的Tm值和A-T含量有关,A-T含量高则Tm高。
【简答题】改错 Dear Michelle, I'm very exciting!Today is my first day at a new school in Australia.The school I study at is a government school.Although I'm new to my classmates,the teacher asks me to introduce m...