取一个假设含一对同源染色体的受精卵,用15N标记细胞核中的DNA,然

取一个假设含一对同源染色体的受精卵,用15N标记细胞核中的DNA,然后放在不含15N的培养基中培养,让其连续进行两次有丝分裂,形成的四个子细胞中含15N的细胞个数不可能是

A1                    B2                     C3                    D4

答案

A

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