染色体的主要组成成分是( )
A:蛋白质
B:纤维素
C:脂肪
D:蛋白质和DNA
⑴Are you cold? ____
⑵Would you like some fruit? ____
⑶Do you like dumplings? ____
⑷What's your favourite food? ____
⑸What's on the table? ____
A. Dumplings.
B. Yes, I am.
C. My favourite food is meat.
D. Yes, please.
E. Yes, I do.
光合速率受光合产物从叶中输出速率的影响。某植物正处于结果期,如图①。若只留一张叶片,其他叶片全部摘除,如右图②,则留下叶片的光合速率( )
①10﹣3=0.0001; ②(0.0001)0=1; ③3a﹣2= 13a2 ; ④(﹣2)3÷(﹣2)5=﹣2﹣2.
关于等高线的说法,正确的是( )