①②③是雌性生殖细胞，④⑤⑥是雄性生殖细胞，六种细胞中能结合形成先天愚型男孩的组合是（ ）
①23+X ②22+X ③21+X ④21+Y ⑤23+Y ⑥22+Y
| A．①和⑥ | B．②和④ | C．⑤和⑥ | D．包括ABC |
相关试题
I want a mobile phone which____good pictures．（ ）
A．tookB．is takingC．takesD．take
Look at the labels（标签） of a blouse on the right．Which is TRUE about the blouse？（ ）
A．It's made in China．
B．It's made of silk．
C．It's a hand﹣made blouse．
D．It must be washed in water．
﹣Would you give me some juice， Linda？
﹣____（ ）
A．Yes， please．B．The same to you．
C．Never mind!D．Certainly．
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