问题
单项选择题
关于生殖腺发生错误的是()
A．原始生殖腺约在4～6周末形成
B．缺乏睾丸决定因子决定了卵巢及其生殖细胞的发育和形成
C．原始生殖腺的分化取决于有无睾丸决定因子
D．原始生殖腺有向睾丸或卵巢分化的双向潜能
E．胚胎第12周时，原始生殖腺分化为卵巢
答案
参考答案：E
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关于生殖腺发生错误的是()
A．原始生殖腺约在4～6周末形成
B．缺乏睾丸决定因子决定了卵巢及其生殖细胞的发育和形成
C．原始生殖腺的分化取决于有无睾丸决定因子
D．原始生殖腺有向睾丸或卵巢分化的双向潜能
E．胚胎第12周时，原始生殖腺分化为卵巢
参考答案：E
| 读一读下面的对话，写名称。 | |||
| A: Where is the teacher's office? B: It's on the first floor. A: Where is the art room? B: It's on the second floor; The music room is on the second floor, too. A: Is the canteen on the first floor? B: Yes, it is. And the washroom is on the first floor, too. A: Do you have a TV room? B: No, we don't. But we have a gym. It's on the second floor.
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