单项选择题
A.TtBb和ttBb B.TtBb和Ttbb C.TtBB和ttBb D.TtBb和ttBB
A.7932株 B.3966株 C.1983株 D.1322株
A.9:3:3:1 B.3:1:3:1 C.1:1:1:1 D.2:2:1:1