-- Mum, can I go to the zoo with Jack?
-- When your homework , you can.
A:is done
B:was done
C:has been done
(1)请你指出图甲中连线的错误:____
根据题意,回答下列问题:
牛的无角基因对有角基因(b)为显性。一个有角母牛和无角雄牛杂交,生了一个有角小牛,则雄牛的基因组成是()