两个杂合体杂交,子代只有一种表现型,则这两种杂合体的基因型可能是()
A:aaBb和AAB
B:AaBB×AAB
C:AaBb和AAB
D:AaBB×aaB
Young Club ____(found) two years ago to provide training for students and unemployed young adults aged 18 to 21.
Everyone was silent as the judge ____ (宣布) the winner of the competition.