下列各项有关遗传学概念的描述,正确的是( )
A:一条染色体上只含有一个基因
B:一对相对性状分别由一对基因控制
C:一条染色体上都含有两条DNA
D:不同种生物细胞含有染色体数目相同
A.What time is it?
B.Is that the garden?
C. Is it warm today?
D.Where is the library?
E.What's the weather like today?
⑴____ A.music B. can C. pencil D. cousin
⑵____ A. always B. some C. sister D. subject
⑶____ A. mine B. tidy C. nine D. habit
⑷____ A. thank B. happy C. want D. jacket
⑸____ A. dear B. pear C. near D. hear
下面对人体“动脉”的叙述不正确的是( )
图1是我国耕地资源和水资源南北分布的差异图,图2是南水北调工程局部示意图,读图回答下列问题。