两对基因(A-a和B-b)位于非同源染色体上,基因型为AaBb的植株自交,产生后代的纯合体中与亲本表现型不同的概率是()
A.3/4
B.1/4
C.1/2
D.1/16
参考答案:A
Many students in our school _______ the old and they usually offer their seats to them on buses.
A.worry about
B.care for
C.agree with
D.take care
A.一支普通铅笔的长度约为50cm
B.教室天花板到地面的距离约为3m
C.一件普通衬衫的质量约为2kg
D.一个普通中学生的体重大约是50N